Access to the path '.dtsx' is denied ?

Hi ,

I have created SSIS package earlier and it was working greate as per our requirement. After very long period i have open it foe modification and try to build. It was not build and give me error message. Below are the error message-

Error Detail-->

"Error 2 
System.UnauthorizedAccessException:
Access to the path 'N:\SSIS\GC_Sales_Commission_Report\GC_Sales_Commission_Report\
bin\GC_Sales_Commission_Report.dtsx' is denied.    
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.File.SetAttributes(String path, FileAttributes fileAttributes)
at Microsoft.DataTransformationServices.Project.DataTransformationsProjectBuilder.BuildIncremental(IOutputWindow outputWindow)  0 0 "

To overcome this i donot have any good appraoched, please suggest me any goos approach.Thanks