Need help with unknown rebuild errors!!!

When I open a particular main assembly I have rebuild errors. I then go into the subassembly look at the options and hit OK. Ctrl Q, Save, close then back into the main assembly. rebuild error is gone, Ctrl Q rebuild error still gone, save, close main assembly, open main assembly back up and rebuild errors are back. I am using SW 2011 SP 2.0

Thanks in advance

SolidworksAssemblies