In Whidbey (Microsoft.Net v2.0), DateTime.Parse() throws an exception if the date separator is a space.  This was fixed in future QFEs, including the Whidbey Vista release, so you'll only see this on XP, 2003, etc and not on Vista.

This is fixed in future versions, so if you apply most any QFE to .Net 2.0 RTM this bug'll be fixed.