The problem from what I've found looks to be a bug in SPServices 0.7.2. I've found this on line 1206:
opt.completefunc(cachedXML, status); // When the call is complete, do thisif ( $.isFunction( opt.completefunc ) ) { opt.completefunc( cachedXML, status ); // When the call is complete, do this }
Let me know if that fixes you up...
Cheers,
Matthew