Naith,
I am not sure what drivers are used to run the APS. If the p2ssyb10.dll is used (Crystals Sybase driver) then you will probably have better luck if you switch to an OLDER driver (our APS is running on SQL server). Yeah.. I know.. but I report off sybase and all the drivers past 8.0.0.10 have had one flake or another, usually resulting in designer crashes - esp with datetime paramters and SP's. Sometimes everything looks fine, but there just isn't any data returned. This is now a known and documented bug after I spent a month trying to get them to admit their driver was bad (although try to find a list of "known and documented bugs"! rofl!).
Anyway, if the APS uses this driver, you probably would want to try the older driver. If you can't find it, post your email here and I will send it to you.
Lisa