cabarc.exe not working well

Question

hi I am using cabarc.exe in php to extract file from the .cab file. it gives out put as "unable to open file: xxx.cab"; when i copy command and run from command prompt it work fine. i have checked permission all files have same permission. my code is

$command = $CFG->dirroot."cabarc.exe x \"".$cabFilePath."\" $tempDir\\";

 $return = -1;

 ob_start();
 //extract cab file in temp folder
 $output = system($command,$return);
 //exec($command,$output,$return);
 ob_clean();

thanks for help