Hi Ludek,
Thank you very much for prompt reply. That IS a lot of information! I feel like a dinosaur and we are 
I didn't even know VS2008 comes with CR SDK for .Net but your blog (this blog) helps.
First of all, I ran such a simple .NET test program. Same thing, it failed to show reports (created in CR 10.0.0.533) with VB UFL, however, it didn't crash, it did give an error message:
---------------------------
Crystal Report Windows Forms Viewer
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The Visual Basic UFL that implements this function is missing (or U2lcom.dll is missing).
Error in File C:\Users\susanl\AppData\Local\Temp\Command Sets {2C646B5D-ABFB-4416-8133-1F24ECB053AA}.rpt:
Error in formula <Operator>.
'hecMiscOperatorName
'
The Visual Basic UFL that implements this function is missing (or U2lcom.dll is missing).
---------------------------
OK
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Does it mean there's no hope of reusing the close to 100 factory made reports with VB UFL in our web app without modification to the reports, no matter we upgrade Crystal Report or not?
What do you think of these ideas:
1. Find a workaround for UFL and continue to use the unsupported CR 10 runtime, although I have none on top of my head. We use UFL to get the operator name and decrypt data based on some database settings.
2. Use VB6 program to export the reports as pdf and use them in web app from there.
3. Upgrade CR. However, we will still need to upgrade all those ~100 reports, right? Use .NET ufl? BTW, we use both VS2008 and VS2010, more the latter. The SDKs for both are free, right? Which version comes with the full CR Designer?
Sorry, I have 10 year worth of questions here. Thank you for your patience.
-Susan