I am looking for an open source repository built on php,and uses mysql ,right now I am using eprints but somehow i am not convinced with it,could any one suggest me the best stable open source repository(Data Management System) Thanks
The only widely used repository that I know of which uses PHP is Opus (http://elib.uni-stuttgart.de/opus/doku/about.php?la=en), although it's not technically open source. Not having used it, I can't give you much more info, although from investigating it before I think the code is free to use, but you have to pay to run production instances.
Are you looking for a straight digital repository, or would a content management system suit you better (of which I'm sure there are a million written in PHP)?