Indesign updating Links

Why InDesign asks for Updating Links in a same network(same subnet). The process is if i saved a file on server in some location, then i will open that same file from another system in the same network, then indesign asks for relinks. can any one helps me please please

Model: Gmac
Browser: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv: Gecko/20070802 SeaMonkey/1.1.4
Operating System: Mac OS X (10.5)

Check the clock on both computers and the network, it is possible that the clocks are set wrong. So the other machine thinks that the image needs updating. We run into this problem at work when daylight savings time takes effect.

Thansks for your reply , but i checked the time and date at server end and user end. Time also same. it will happening suddenly