Write file can't work ?!? :-(

Hi. I am trying to create little counter: I can't open file for writing. I've tried different params: "w", "r+", "wb" ... nothnig works I am using IIS 5.0 , and I have set permitions to read & write files on server. ============= source code =============== if(is_writable("counter.txt")==TRUE) echo "File is writable"; else echo "File is NOT writable"; echo "<br>"; $fd = fopen ("counter.txt", "r"); $my_count=0; while (!feof ($fd)) { $my_count = fgets($fd, 4096); } fclose ($fd); $fd = fopen ("counter.txt", "wb"); if($fd==TRUE) { $my_count++; fputs($fd, $my_count); fclose ($fd); } echo "Your are user no:"; echo $my_count; ============= end source ================ but after execution PHP says that: File is writable Warning: fopen("counter.txt", "wb") - Permission denied in c:\inetpub\wwwroot\PSK\user_no.php on line 27 Your are user no:8 Whay can't I open file for writing??? Thanks for help!!!