I'm having trouble with AutoCAD 2011 when I attempt to freeze layers from Xref's with the layer manager or paper space.
 
I'm prompted with invalid keyword option and it ingnores my attempt to freeze the layer, or change any of the layer properties.
Any thoughts?
Thanks,
Tweaker.
 

Does this happen in all drawings or just this one?If this happens only in one drawing, try running a PURGE and AUDIT on the drawing and all the Xref's in order to clean them and clear them of any errors.If this happens in all drawings, try running a Repair.