[Zope-DB] No module named ZDBase

[D. Rick Anderson]

I've found this issue mentioned a few times, but I've yet to see 
somebody provide a fix.
I have :
RedHat 8.0
Zope 2.6.2 (was 2.6.0)

this is one of 3 servers configured this way, but the only one that does 
this.

When I click on the 'Advanced' tab in a Z SQL Method I get the error:

ImportError
No module named ZDBase

which is a problem because some of these need to return more than 1000 
records, which of course I can't change without that tab (I could 
probably figure out what to call, but that's not the point). I started 
on 2.6.0 and thought that maybe an upgrade would fix it, so I installed 
2.6.2 (installed, not upgraded) and copied the Data.fs files and the 
lib/python/Product folders for the products I need. The server came back 
up just fine, and all the connections work, but the error is still 
there!  I looked all over the place for ZDBase (it says the call is in 
lib/ZODB/Connections.py but I can't find a reference to ZDBase there). 
ANY help would be greatly appreciated ..

Rick