BDE 4.51 and BDE 5.0, and Oracle

I have a problem with versions of the BDE and Oracle.
The application in Delphi3 that I wrote works fine when using: BDE 4.51 and
Oracle 7.34
When I installed the BDE of DElphi5 and Oracle8 problems appeared.
(I did install the patches for Local SQL and Oracle8, I use Oracle73 driver
with Oracle73 and ORA8.dll with Oracle8, and also the Clients of Oracle that
belong with the version number of Oracle)
The application uses a lot of  'Locates' to get to the right record.
Sometimes the Locates can't find the record, when the cursor is in the right
table and even if the cursor is right on the correct record. I can read the
ID with FieldByName, but when I search for the ID with Locate, it returns
False.

It is a very serious thing, because it does not occur on every Locate, only
I think, on Locates that are part of a function that operates in another
table.

Maybe this can also be helpful, it works well with ACCESS.
Since I am not sure when the Locate is missing the record, I hope some one
else can help me.
I would be very greatful,
Deborah