SSIS Package Not Executing

Hi all
Actually we are getting zipfiles as source
for unzipping the files we created utility package (anyone can use that package for unzipping the files)
so 2persons executing ssis package sametime bt utility package is failing for 1person
 
Error Message:
Error 0x80070020 while loading package file "D:\SSIS_IOM\SSIS_Util\Util_UnZip.dtsx" into an XML document. The process cannot access the file because it is being used by another process.

Please help this problem:

Thanks
Ram