MP3 problems

Not too sure whre the probem lies, but it would appear to be the LAME codec.
I had to batch convert a pile of WAV files to 128kbps MP3 for a teacher resources site, where they were to be embedded into a flash player before upoading as resources.
Every single encoding from WL6 Batch conver tool failed with errors.

In desperation (There is no access to Fraunhofer in WL 6) I tried using AVS Audio Convert using fraunhofer and they all passed first time.