>I've discovered the cause of my problem with vfpcompression.fll. In my case, I had a SET UDFPARMS TO REFERENCE command. Switched back to the default SET UDFPARMS TO VALUE - it works perfectly. Thanks to Craig Boyd and all for comments, Denis

I always have SET UDFPARMS TO VALUE as default. If I need to pass by reference, I use @myvalue.

From "Hacker's guide .." : "If you set SET UDFPARMS TO REFERENCE, all parameters are passed to functions by reference. Don't do that!"