I got the error while trying getTables() in live api, though none of the other calls are working either.
Sybase query to get list of user tables would be Select name from sysobjects where type="U" or there is also an inbuilt stored procedure "sp_tables"
I think the error means DSP failing while trying to get list of all user defined schemas which could be the first step of any DSP call.
Any chance of finding where its getting executed so we can try alternate query to see if this is the issue?