Hi there,
Thanks for all your comments about the annoying UNHANDLED EXCEPTION ERROR. We also have experienced this situation in both Business Objects 5.1.2 and 5.1.3, and in most cases deleting the universes from c:\ or letting the client machine using more swap memory fixed the problem.
But now things are getting worser, since we faced an upgrade to SP6 (Business Objects 5.1.6, Web Intelligence 2.7.2). When our users try to edit the existing reports (made with the 5.1.2 and 5.1.3 versions) using ZABO clients through a new BO SP6 server they always get the UNHANDLED EXCEPTION ERROR in cube50.dll. 
If we try to edit / refresh documents with the full client in both SP3 and SP6 versions everything works fine, so I asume the problem may be related to the Zabo SP6 server.
We opened a case with Official Business Objects Support and the only answer that we got is that there may be some kind of incompatibility between SP3 and SP6, and suggested to open and save the reports with other name 
(didn’t work) or get them all redone in the newer version 
(really madness, since we have lots of legacy reports).
Is anyone experiencing the same problem? Any advice would be really appreciated, i’m afraid we will have to abort the upgrade and stay in BO SP3.
Our Server: Windows 2000 Server SP2
Our DataBase: Oracle 8.1.7 (repository and data)
Our Clients: Windows 2000 Professional SP2
AGRodeja (BOB member since 2002-09-03)