Error while deleting a file which is in a folder which inturn in workspace

12:20:42.309 DELETE (FAILED: Conflict [(pre||post)-condition failed: x:concurrency-lock-denied]) Hello.java (C:\CFolder1\WSF1\WSF2\Dev\HelloWorld\Package\Hello.java)

--- Problem summary: ---

12:20:42.309 DELETE (FAILED: Conflict [(pre||post)-condition failed: x:concurrency-lock-denied]) Hello.java (C:\CFolder1\WSF1\WSF2\Dev\HelloWorld\Package\Hello.java)

I am getting above error while deleting a file which is in a folder which inturn in workspace