i just tried my first listing ever - for a CD. i got the same API error with the same general API description. i contacted support, and they elaborated that i was errored because i mentioned Western Union and Money Gram in my listing, and these are prohibited methods of payment at ebay. Problem is that i DID mention them in my sellers details as specific methods of MOs that are NOT ACCEPTED! so i learned that ebay does not scrutinized this aspect of a listing, whether or not you accept them. I gues that WU and MG are SO bad that you can't even MENTION their names in you listing at all!
so i got around this by saying that "specifically money orders that are initialed with WU or MG or the like are not acceptable forms of payment." and the listing went right on thru...
oh yea, the "error check" did not catch this, so i think that whatever you have in your "seller details" (which is where I had this information) is not checked by the error check tool... so it must only check basic things in the listing...? Yea? maybe?