R help - Jun 2007 - unknown type 63, perhaps written by later version of R

Dear all,
 
I'm using R-2.5.0.
 
If I type: 
 
> load("C:\\Data1\\.RData")
 
I get: 

Error in load("C:\\Data1\\.RData") : 
        ReadItem: unknown type 63, perhaps written by later version of R
 
Any idea why?
 
Many thanks,
 
Mario
 
Dr Mario Cortina Borja; Senior Lecturer in Statistics
MRC Centre of Epidemiology for Child Health, Institute of Child Health,
University College London
Tel: 44(0)20-7905-2113; FAX: 44(0)20-7905-2381; M.Cortina@ich.ucl.ac.uk
 

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