Actually I just rebooted my computer (which I should have done to beging with even though it didn't ask me to reboot) and now it's working, even though on the first try it showed a blank form, the second time and afterwards it works.

It was hanging at this line Sergey:

Thisform.oWB.OBJECT.Navigate2(Thisform.oParam.PdfFileName)

Getting a message about Adobe Acrobats update, hope it doesn't mess it up ;-).