I just installed SP1 for VS2010, and since then I get error messages from Resharper for stuff that used to work and be ok for Resharper (5.1) before.
The error messa
I would try deleting the _ReSharper.{SolutionName} directory completely if clear cache fails.
_ReSharper.{SolutionName}
You might want to close VS2010 before you do that.
EDIT: Try this only if @Andrew Finnell solution doesn't work.