I am trying findout whether a process is already running in Windows 2000 Professional using a perl script that is given below. Sometimes I am getting the following error:

Win32::OLE(0.1603) error 0x800401e4: "Invalid syntax"
    after character 0 in "WinMgmts:{impersonationLevel=impersonate}!//
+"
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Any idea why it is giving this sometimes not always.

sub checkProcessExists {
    my $newPid = $$; // Get Process id
    my $file; //old Process id is stored in this file
    my ($flag, $oldPid);

    unless (open (PRID, $file)) {
        $flag = 0;
    } else {
        $oldPid = <PRID>;
        chomp ($oldPid);
        close (PRID);
        $flag = 1;
    }

    if ($flag) {
        my $CLASS = 'WinMgmts:{impersonationLevel=impersonate}!//';
        my $WMI = Win32::OLE->GetObject( $CLASS ) or print ("OLE, GetO
+bject error: " . Win32::OLE->LastError());

        my $pid;
        foreach my $proc (in $WMI->InstancesOf('Win32_Process')){
            $pid = $proc->{ProcessId};
            if ($pid == $oldPid) {
                $flag = 1;
                last;
            } else {
                $flag = 0;
            }
        }
    }

    if (!$flag) {
        unless (open (PRID, ">$file")) {
            print ("Unable to open $file");
            exit();
        } else {
            print PRID $newPid;
            close (PRID);
        }
    } else {
        print ("$name (PID: $oldPid) is still running. Try again later
+");
    }
    return $flag;
}
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Originally posted as a Categorized Answer.