R help - Mar 2013 - help.search not working - returns "readRDS(file) : unknown input format"

Hi all,

I'm using R 2.15.1 under RStudio on a WinXP computer.

This morning as I started up RStudio, I noticed that there was
something wrong with the help database.
I entered and received the following:

??'xls'
#Error in readRDS(file) : unknown input format


writing help.search('xls') returned the same error. a plain help(plot)
worked fine/  Some googling led me to close RStudio, remove the .RData
and .RHistory I was using,
but the same error  remained. Another googling suggested that I'd use
the rebuild=T option, so I ran

lapply(rownames(installed.packages()),function(x)help.search('',package=X<-x,rebuild=T))

Now there is no error, but help.search cannot find anything - it seems
as if the database is empty.
Does anyone have experience with a similar error?

Best regards,
Gustaf



-- 
Gustaf Rydevik, M.Sci.
tel: +44(0)74 253 760 42
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skype:gustaf_rydevik