OK, I have several games that require steam to play. I almost always play in offline mode.  Today I permitted steam to update two games.  (I have auto update OFF to protect Skyrim from an update screwing up SKSE, etc.)  I was able to play all the games updated except for CIV5.  It won't let me play Civ5 in offline mode.  I keep getting a dialog box that says the  'steam serves are too busy,' and an "error code (53).'  I retried about 15 times. 
Might someone experienced with steam advise me on whats up, and what to do?  Thank you all.
 
Successfully addressed.  Thank you both!