Problems while trying to look at the code from Eclipse

Hello

I'm having problems trying to look at ABAP code within Eclipse, every time I try to open a program i get this error:

The editor cannot be shown because the content cannot be synchronized with the back end: Synchronize Content Result for /ABAPsystem/.adt/programs/programs/zprogram/zprogram.approg; System failure: "Exception condition "NOT_POSSIBLE" raised." (For detailed information, check the generated short dump in transaction ST22 of system ABAP).

The system configuration:

SAP_BASIS:    731    0004

SAP Kernel :  721_EXT_REL

We just upgraded from kernel 720_EXT_REL to 721_EXT_REL to enable debug within Eclipse, however I can't see any code now. Basis has no idea what it could be, they told me they haven't changed anything in the configuration.

Any help would be appreciated.

Thanks!

Daniel H.