There are a couple factors that could cause you to receive an Error #4100, such as;

Network Related- Network errors which prevent part of the game from being downloaded from our servers. These errors are intermittent, and waiting a few minutes before resuming the download typically resolves the issue. We are actively working with our service provider to diagnose and eliminate these problems.

Low Disk Space - The disk to which the game is being downloaded does not have enough free space for the game. Please check the size of the game shown below the download progress, and verify that it is less than the remaining free space on your disk. For new installs of the GameTap plugin, this disk should be C:. For users who migrated from GameTap 3.5 or lower, this disk should be the same disk which previously held your downloaded games.

If you have low disk space and need to move your default download location, follow the instruction in this knowledge base article.

http://support.gametap.com/selfservice/ ... .do?id=348