Microsoft claims there is a limit of approximately 7,000 words for AutoCorrect. Most people run into memory resource problems (causing Word to crash) long before they reach the limit. AutoText is limited to Word's file size limit of approximately 32MB -- this file size would also include all customizations and macros stored in the normal.dot (if that is your default storage file).
Since you are working directly on a server, you would have to look to them for a solution.
