Hi, I got a similar problem while opening csv files (file has wrong format) and the resolution was to re-register the jet-engine-files (in system32):

regsvr32.exe Msexcl40.dll
regsvr32.exe Msexch40.dll
regsvr32.exe Msrd2x40.dll
regsvr32.exe Msrd3x40.dll
regsvr32.exe Msltus40.dll
regsvr32.exe Mspbde40.dll
regsvr32.exe Mstext40.dll
regsvr32.exe Msxbde40.dll

http://support.microsoft.com/kb/209805/DE/