[R] R2.0.1 for Mac OS X 10.3 problem

[Greg Arnold]

This combination was operating satisfactorily until I tried updating 
lme4 and Matrix.  My attempts to do this ultimately broke R.  The R 
console appears briefly, then collapses.   I have tried downloading and 
reinstalling R without success.  Typing 'R' into Terminal gives the 
error message bring up the usual introduction, then the error message:
Error in methods:::mlistMetaName(mi, ns) :
         The methods object name for "coerce" must include the name of 
the package that contains the generic function, but there is no generic 
function of this name
Fatal error: unable to restore saved data in .RData

Can anyone help?

Greg