There's always a way to get more information :)
unfortunately, except for the linux based releases there's no way to trace AXL separately so you'll have to look at the dbl traces instead.
In there you should find some query that will probably look something like this:
SELECT Name FROM CallingSearchSpace WHERE Name LIKE ''
Hopefully, the error is somewhere in the dbl layer - I don't know if there's a way to trace the bits between your axl client and the dbl layer (it's probably in the ccm logs) on the 4.x CCM train (in the 5.x you have axl as a separate options in serviceability, making it a lot easier to trace how operations pass through the system).
I'd also try more basic search options.. I think "%" without quotes should list all CSS but I'm note 100% sure since I don't use lists. Instead, I use direct SQL queries which is what you can also try.. you have the SQL query template above, just plug it into an executeSQLQuery AXL element and fire away. The result will look something like this
css1
css2
which is easily parsed (list all elements matching the following xpath query: //result/row/name).
While AXL is powerful and useful, get and list operations may often not be exactly what you need. E.g. if you want to know which lines (phone numbers) a phone has, it's much quicker to send a single SQL query rather than to do a getphone followed by a getline for each line. Naturally it means a bit more work and thinking - but with CCM 5 you get the ability to write to the DB via axl as well (and for certain things you currently even must write into the DB as certain functionality that was present in ccm 4.x is no longer present in 5.x as far as axl is concerned but I'm digressing).
