Hello Roberto,
we have solved the bug you have reported. The quickest way to let you have a workaround is, we believe, providing you with a snapshot of what will become PPL version 0.5. You can find it in our snapshots' area, accessible by FTP at
ftp://ftp.cs.unipr.it/pub/ppl/snapshots/
and by HTTP at
http://www.cs.unipr.it/ppl/Download/ftp/snapshots/
Of course, this operation is a bit rushed and not without risks since the snapshot did not undergo thorough testing and because version 0.5 brings some changes that are not backward compatible (_most_ of which are listed in the NEWS file). However, we will give you the maximum of assistance we can. Please do not hesitate to post the questions you may have to ppl-devel@cs.unipr.it (you have just been given full write permission to that mailing list) for the quickest response time. Thanks a lot for helping us improve PPL.
Thank you for the quick response! I integrated the new version 0.5pre8 which drastically improves what I can demo.
-Ken