Crystral reports 'Object reference error' on Production server

[Von Shean]

I have developed reports using CR 9.2.33. It works fine on the development
machine. But when i moved it to the production server i had to install CR on
it.
So i copied 4 CR dlls in the bin folder. These dlls are:.
CrystalDecisions.CrystalReports.Engine.dll
CrystalDecisions.ReportSource.dll
CrystalDecisions.Shared.dll
CrystalDecisions.Web.dll

Now when i view reports from th eproduction server then i get an error that
says
'Object reference not set to an instance of an object'

Please help!!

Regards,