Infragistics PVDate control does not dropdown calendar on Windows server 2008 R2

Hi All
We are moving an old vb6 application to windows server 2008 R2. VB6 IDE is now installed on Windows 7.
We are using infragistics PVDate9.ocx for our date controls.
When compiling and running the application on the window7 computer, the control drops down the calendar. The same EXE when deployed on 2008 R2 does not drop down the calendar but other than that works OK. No error when clicking on the little arrow to the right of the control.

Infragistcs are of no help. They claim that it is not supported any more (makes sense - this control was published in 2001 or close).

Yes, we can replace this component with MS DatePicker (part of MSCOMCTL2.ocx) which works OK on 2008 but the behavior of the MS one is different. It has different properties and it does now allow for null or empty value which our code is relying on. The replacement will require many hours of diving into old code and rigorous testing.

I am looking for some ideas on why the pvdate control works on Windows 7 and not on 2008 server?
Thanks
Myalo