Problem on file_exists()

Dear all I had a folder which the path is : (\\nedcoraa\pdf_reports\dealing room\report) it stores a lot of PDF reports in there. I'm trying to use the file_exists() function to detect if a specific file exist in this folder, but i got a problem is : It seems that php can go through (\\nedcoraa\pdf_reports) but it can't go through (dealing room) folder. i had made test on it, i moved a file into (\\nedcoraa\pdf_reports), then php can detect it, but if i move it to (\\nedcoraa\pdf_reports\dealing room), then it can't detect the file! why? I'm using php in windows NT IIS environment! Please help me! -- Thx a lot! Jack nedcor4@nedcor.com.hk