Have you ever seen this error when trying to re-image a computer using Microsoft Deployment Toolkit?
A connection to the deployment share could not be made. The deployment will not proceed.
Connection OK. Possible cause: invalid credentials.
You double-checked everything. The credentials are correct for the service\local account you created with access to the share, you double-checked both bootstrap.ini and customsettings.ini, and you verified that the UserID, UserDomain, and UserPassword variables are correct but you still get this error.
Not only that, this doesn't seem to be a widespread issue; You only see this error on one or two computers.
The root cause of this issue has nothing to do with your MDT setup at all. In fact, this error is misleading. "Connection OK" means exactly what it says. Your computer was able to contact the MDT share just fine. But "Possible cause: invalid credentials" is the misleading part. To fix the issue, make sure that the system date and time is set correctly on both the computer serving the MDT deployement share, as well as the time and date on the computer you are trying to re-image. There is a good chance that one of the machines has a dead CMOS battery or the date and time was reset back to factory settings (which means the year is set for 2004 or 2008 or something like that). Just make sure the date and time is correct then try again.
More detailed information about this issue is located here: http://social.technet.microsoft.com/Forums/en/itprovistadeployment/thread/1c2a306d-e38d-4347-8761-3810513a139e