End of stream when selecting computer

[kane22]

Title: End of stream when selecting computer

Version: 3.1.2

OS: Windows 7

Java Version: 1.7.0_06-b24

Description of Problem:

When im on my server and players try taking a computer / monitor / central processing unit (etc..) they get End of stream. This is beginning to annoy me becuae im a computer person but i can only use the ones i place on the first day of server operation. Server has 4gb's of ram, and i dont have this problem in single player

Error Messages:

Disconected by server - End of Stream

Error Log:

[kane22]

PS : Everyone on the server is creative (2 people)