Hi Dawn -
Sorry for the trouble. Are you having problems with the "attach this email" or the "link to this email" option?
With the "link to this email" option, this situation you described can happen when the Gmail cannot find the email that the link is pointing to. Usually this is a result of the email being in a different email account, or not longer existing (because it was deleted)
So, there are a couple of things you can do.
1. Make sure you are only signed in to the Gmail account you use with GQueues.
2. Make sure you are creating tasks only from that Gmail account.
3. Make sure you haven't deleted the email message. If the message gets deleted, then the link to that message won't work.
Does this help at all? If not let us know more details and we can continue to help troubleshoot.
-Cameron