[Update - 3:45 GMT] DO NOT DOWNLOAD ANYTHING
If you receive ANY email which seems coming from Mt.Gox asking you to download something (certificate, generating program, etc), DO NOT DOWNLOAD. Do not either input your password on any site which is not MTGOX.COM.
This is malicious - avoid !General Rule
- Never download unsolicited attachments
- Never click a href link in an email (always go direct via browser to homepage)