Urgent - Multi User Database

Hi All,

I have written a Multi-User App in VB6.0 (sp4) communicating to the Clients Access (2000) database. First User all is ok, but when other instances of the App log-in, I get "Must use an Updateable Query",
my connections settings are as follows:
ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Directory\Access.MDB"

RecordSet definitions are as follows (e.g.):
rs.open "some sql statement",conn,adOpenDynamic,adLockOptimistic

From what I have been able to find in various doco, these settings should allow multiuser updates to the tables in the database. ( or am I wrong again ?).

Please help - Urgent!!!
many Thanks

RobZ