Job to Execute SSIS package fails

This question has been asked earlier in this forum. But, I still didn't get the correct resolution of my problem.

I am trying to run the DTS package from my filesystem.

Command Line:
/FILE "C:\SSIS\IS\bin\Package1.dtsx" /MAXCONCURRENT " -1 " /CHECKPOINTING OFF

Executed as user: FILESERVER\SQLServiceQA. The command line parameters are invalid. The step failed.

Can anyone please let me know whats the problem with it.

I am not using any Script Task in the package.

Thanks.Does it run if you execute the same command line as the same user using DTExec? If so then you should probably post to the agent forum. If not then what errors do you get when running it from DTExec?

Thanks,
Matt