I/O problems frequently occur when mxd files are browsed in arcmap9.x.

I/O problems frequently occur when you browse mxd files in arcmap9.x. The error message is as follows:
One or more layers failed to draw:
Fdo error: 0
Network I/O Error

Which of the following problems may be caused and how to solve them.
Solution:
1. There is a problem with the local network service and the packet delay. Use the Ping-T command to disable the local firewall.
2. The mxd file is damaged and mxd doctor is used.
In Versions later than 3.9i, The open_cursors initialization parameter must be at least 2000.
4. Patch SDE.