Well, this one was easy: I was using maven to import sfapi, however, the version in the maven repository is compiled against 3.3, causing this error.
Easy fix: Download the sfapi.swc from the offcial page and install it on your maven repo with somehting like "customversion" and compile versus that one.
----
By the way, you see against what version it was compiled by unzipping th swc, and checking out catalog.xml
