Thanks guys 
 
Yes, the Classes are in a LabVIEW Project Library (for namespacing). But the Dev Env is 2009.SP1 
 
I am not the author of the code (and not a work at the moment) but I am pretty sure the Class being read has two Classes as data members, one of which would be child class at runtime. 
Is there any way to 'load it' - I mean the code its all there in src tree/project, and it was all working previously, so I am not sure why now it fails. I am also pretty sure those methods are called on the Real Time, and that has been working fine too. 
Cheers 
-JG