I know that SoS doesn't officially support 2005 yet, but I think I have to post this issue.
There is a problem working with SoS from at least VS2005 RC0 (September's release) while getting latest version over the folder in web project that contains new file added by another user. Visual Studio shows a message box that source safe provide causes an exception and will be disabled. Refresh project tree was done, even sos database was deleted before this operation and this didn't help. Now we have to manually get latest version from SoS client.
VS2005 RC0 & SoS 4.1.2: get latest version raises except
Moderator: SourceGear
4.1.2 + VS8 RTM crashes...
We had the same problem with Beta2, I used to delete the solutions local folder and SOS files from Application Data folder, login once with the regular client to set the destination folder and then use open from source control option of VS 8... It works a couple of times after this procedure... and then you have to repeat it...