HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3 ;
looks identical to mine; thought the reason for error could have been the (Standard) REG_SZ WMP11.AssocFile.MP3; but you have same entry:
-------------
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3]
"PerceivedType"="audio"
@="WMP11.AssocFile.MP3"
"Content Type"="audio/mpeg"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\OpenWithList]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\OpenWithList\ehshell.exe]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\OpenWithList\iTunes.exe]
@=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\OpenWithProgIds]
"WMP11.AssocFile.MP3"=hex(0):
"QuickTime.mp3"=hex(0):
@=""
"iTunes.mp3"=hex:
"foobar2000.mp3"=hex:
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\ShellEx]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\ShellEx\{BB2E617C-0920-11D1-9A0B-00C04FC2D6C1}]
@="{9DBD2C50-62AD-11D0-B806-00C04FD706EC}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mp3\ShellEx\{e357fccd-a995-4576-b01f-234630154e96}]
@="{9DBD2C50-62AD-11D0-B806-00C04FD706EC}"
-------------
HKey_Current_User\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\mp3 :
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.mp3]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.mp3\OpenWithList]
"a"="MovieMaker.Exe"
"MRUList"="fbdeca"
"b"="MOVIEMK.exe"
"c"="audacity.exe"
"d"="foobar2000.exe"
"e"="EAC.exe"
"f"="iTunes.exe"
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.mp3\OpenWithProgids]
"WMP11.AssocFile.MP3"=hex(0):
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.mp3\UserChoice]
"Progid"="foobar2000.MP3"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000\.mp3:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3]
@="MPEG layer 3"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\DefaultIcon]
@="C:\\Program Files (x86)\\foobar2000\\icons\\MP3.ico"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell]
@="open"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell\enqueue]
@="Enqueue in foobar2000"
"LegacyDisable"=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell\enqueue\command]
@="\"C:\\Program Files (x86)\\foobar2000\\foobar2000.exe\" /add \"%1\""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell\open]
@="Open in foobar2000"
"LegacyDisable"=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell\open\command]
@="\"C:\\Program Files (x86)\\foobar2000\\foobar2000.exe\" \"%1\""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell\play]
@="Play in foobar2000"
"LegacyDisable"=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shell\play\command]
@="\"C:\\Program Files (x86)\\foobar2000\\foobar2000.exe\" /playnow \"%1\""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shellex]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shellex\ContextMenuHandlers]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\foobar2000.MP3\shellex\ContextMenuHandlers\Fb2kShellExt]
@="{511D48AF-9E45-4CB8-8F02-9C1BE4BC3CF8}"
"IsDefaultAction"=""
HKLM\Software\Classes\WMP11.AssocFile.MP3 :
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3]
@="MP3 Format Sound"
"EditFlags"=hex:00,00,11,00
"FriendlyTypeName"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,\
00,6f,00,6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,\
32,00,5c,00,75,00,6e,00,72,00,65,00,67,00,6d,00,70,00,32,00,2e,00,65,00,78,\
00,65,00,2c,00,2d,00,39,00,39,00,32,00,35,00,00,00
"PreferExecuteOnMismatch"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\DefaultIcon]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,\
00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,77,00,6d,00,\
70,00,6c,00,6f,00,63,00,2e,00,64,00,6c,00,6c,00,2c,00,2d,00,37,00,33,00,32,\
00,00,00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell]
@="Play"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell\Enqueue]
@="&Add to Windows Media Player list"
"MUIVerb"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,\
6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,\
00,75,00,6e,00,72,00,65,00,67,00,6d,00,70,00,32,00,2e,00,65,00,78,00,65,00,\
2c,00,2d,00,39,00,38,00,30,00,30,00,00,00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell\Enqueue\command]
"DelegateExecute"="{45597c98-80f6-4549-84ff-752cf55e2d29}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell\open]
"LegacyDisable"=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell\open\command]
@=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00,61,00,6d,00,46,00,69,00,6c,\
00,65,00,73,00,28,00,78,00,38,00,36,00,29,00,25,00,5c,00,57,00,69,00,6e,00,\
64,00,6f,00,77,00,73,00,20,00,4d,00,65,00,64,00,69,00,61,00,20,00,50,00,6c,\
00,61,00,79,00,65,00,72,00,5c,00,77,00,6d,00,70,00,6c,00,61,00,79,00,65,00,\
72,00,2e,00,65,00,78,00,65,00,22,00,20,00,2f,00,70,00,72,00,65,00,66,00,65,\
00,74,00,63,00,68,00,3a,00,36,00,20,00,2f,00,4f,00,70,00,65,00,6e,00,20,00,\
22,00,25,00,4c,00,22,00,00,00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell\play]
@="&Play"
"MUIVerb"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,\
6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,\
00,75,00,6e,00,72,00,65,00,67,00,6d,00,70,00,32,00,2e,00,65,00,78,00,65,00,\
2c,00,2d,00,39,00,39,00,39,00,31,00,00,00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shell\play\command]
@=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00,61,00,6d,00,46,00,69,00,6c,\
00,65,00,73,00,28,00,78,00,38,00,36,00,29,00,25,00,5c,00,57,00,69,00,6e,00,\
64,00,6f,00,77,00,73,00,20,00,4d,00,65,00,64,00,69,00,61,00,20,00,50,00,6c,\
00,61,00,79,00,65,00,72,00,5c,00,77,00,6d,00,70,00,6c,00,61,00,79,00,65,00,\
72,00,2e,00,65,00,78,00,65,00,22,00,20,00,2f,00,70,00,72,00,65,00,66,00,65,\
00,74,00,63,00,68,00,3a,00,36,00,20,00,2f,00,50,00,6c,00,61,00,79,00,20,00,\
22,00,25,00,4c,00,22,00,00,00
"DelegateExecute"="{ed1d0fdf-4414-470a-a56d-cfb68623fc58}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shellex]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP11.AssocFile.MP3\shellex\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{031EE060-67BC-460d-8847-E4A7C5E45A27}"
HKLM\Software\Classes\WMP11.PlayMedia :
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP.PlayMedia]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP.PlayMedia\shell]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP.PlayMedia\shell\Play]
@="&Play"
"MUIVerb"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,\
6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,\
00,75,00,6e,00,72,00,65,00,67,00,6d,00,70,00,32,00,2e,00,65,00,78,00,65,00,\
2c,00,2d,00,39,00,39,00,39,00,31,00,00,00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMP.PlayMedia\shell\Play\command]
"DelegateExecute"="{ed1d0fdf-4414-470a-a56d-cfb68623fc58}"