".xls is being used by another process"

Hi guys i am uploading/exporting one excel file and read the datas and storing in to my database table...,

First time its going on well, in the second time the same excel file if i upload once again :

I am getting the error msg as:

"The process cannot access the file 'E:\Files\file.xls' because it is being used by another process. "

whats the problem plz guide me how to solve this one
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