Sharepoint Document not showing version history

Question

Hello All,
I have sharepoint Document library with versioning turned on. When i open a SharePoint word document in word 2007, under review tab I could see version history and i can compare both minor and major version of the very same document. All of a sudden it stopped showing the list of versions available for comparison...it shows the dialog to pick documents to compare with as if the opened document is a locally stored. I do not see the available versions for that documet at all. But i can see the history of version in sharepoint site itself. the problem is when a user wants to comapre the content of a document between versions, we are forced to use office and it supposed to work(it was working...nothing changed other than number of document and versions in that library).

it works for only one user and only on his pc.... and initially i thought its a office isntall issue...but i ahve development SP site with the same set up. if i pull a document on my machine from this dev SP site, it shows all the avaliable version for comparison.

Could someone shed some light on this please.

Thanks,
P.Raaj