Misschien dit?
And I just solved my own dilemma... It seems there was
something wrong with the Report Builder, or more accurately,
I think the Report Builder is now integrated into LO4? I was looking
up the error I got when I came across this answer:
"It means that at some point, an interface was changed to a class,
but an implementer of the original interface was not modified and
recompiled to accommodate this (incompatible) change." (This referring
to the error received - ie java.lang.IncompatibleClassChangeError.)
This got me to thinking that the only "old" reference would be the report builder...
The answer was to remove the Report Builder from the extension
manager list. Once removed, I closed base. Reopened it and tried
opening a few reports. Yep. It worked. I can now opn my reports in LO 4.1.2.3.