In a project we are working with multiple developers AND a build server on a large set of Visual Studio solutions. Problem is that when we have references to a folder with shared assemblies, the relative path to those assemblies specified by a hintpath directive in the .csproj file ends up wrong. The solution file opens up on one system. but fails on another system (reference not found). We also have problems in our automated builds (using the NAnt solution task).
A fix to this is setting a registry entry to the folders with shared assemblies, if the assembly can't be found, this path is checked.
Add a key with any name to HKEYLOCALMACHINE\SOFTWARE\Microsoft\VisualStudio\7.1\AssemblyFolders, and set its (Default) value of type REG_SZ to the path with your assemblies.