Uri, it looks like Jose had the best idea if you're using VFP6. If you're still in VFP5, I'd look at the problem computer to be sure there is only one copy of COMCAT.DLL, then UNREGISTER it. Copy in the new one and try to register it.

HTH
Barbara

>Hi, Barbara and thanks for your reply.
>
>I include the comctl32.ocx in the directory from which Setup Wizard reads the files and makes the distribution set. And my OCX successfully registers itself during the installation. BUT - on my machine there's COMCAT.DLL version 5.0 and the appropriate OCX, while on the computer, on which the problem occurs, version of COMCAT.DLL is older - 4.71 and my version of OCX. Even if I copy 5.0th version of COMCAT.DLL, it doesn't help and when I try to REGSVR32 C:\WINDOWS\SYSTEM\COMCAT.DLL it says that it was impossible to register it. I may replace the treeview control on my form with the old one, (and i'm pretty sure that it WILL help) but why should I?
>
>Best regards, Uri.