Yes, you are right! I have found out that SET COMPATIBLE ON is causing problems.
I use LIKE() function as filter for report in REPORT FORM command.
Is there some solution to that or do I have to make some specific code?

SP2 will address the *known* issues in the Report*.Apps that occur when SET COMPATIBLE is ON or DB4. Until then, you should SET COMPATIBLE OFF if possible.

Unless you are also getting your error when SET REPORTBEHAVIOR 80, in which case this SP2 patch won't make a bit of difference.... but I think I understand from your earlier message that you only see this in the new-style reporting, right?