This is strange.

Does using mkfastmod in a shell works ?

SWORD_PATH=/path/to/your/sword/directory mkfastmod MODULENAME

Be sure not to have any -devel repository set: there is a more recent version of clucene-core in the chinook and diablo devel, but the only sword engine associated with it is in diablo devel. This may explain why indexing fails (index use clucene-core).

Watch this space to follow the "problem uploading sword in diablo" issue:

https://bugs.maemo.org/show_bug.cgi?id=3416