Could not start PsExec service on target machine. Access is denied.

Hi,

I am trying to execute psexec command to remote machine.

My command is

psexec -u domain\user -p password \\machineName -c abc.bat

I am trying from windows 7(64 bit)  machine. The remote machines are xp and windows 7(32 and 64 bit).

In XP machines, it is working and also in some windows 7 machines. But in some windows 7 machines it give message-

"Could not start PsExec service on target machine.

Access is denied."

If I try to execute psexec command from XP machines, it works to all machines.

Suddenly what happen I do not know but one of the windows 7 machine( where psexec was not starting) , psexec started. but not in other machines.

Now I am very much confuse here exactly what happen. and what is the issue.

Please help. It urgent.

Thanks.