This note has been verified with the Tortoise 1.6 Subversion client on Windows XP.

I installed Tortoise 1.6 for subversion on Windows XP. Then I connected to a subversion server using my username and password. Subsequently I tried to check in a file from Emacs, using the VC package. It came with an error saying that the credentials failed.

I solved this problem by copying the contents of C:\Documents and Settings\<User>\Application Data\Subversion\auth to the directory %HOME%\.subversion\auth.