Script Doesnt Respond after 5 iterations

Please Consider the following script and suggest me what to change as the script doesnt responds after 5 iteration.

The Scenario is that:
1) 2 files have to opened in read mode,one contain URLs(chk.txt) and other contains categories(cat.txt)
2) The script reads the first URL from chk.txt file and sends in FF to open.
3) There in FF, cat is read from cat.txt file and send for selection in drop down menu
4) Then everything works fine after necessary steps, but
this scenario stops working after 5 new urls sent from chk.txt file

Provided that The Script doesn't exits..

#include <file.au3>
#include <FF.au3>
$file =FileOpen("chk.txt",0)
$file1=FileOpen("cat.txt",0)
$report=FileOpen("report.txt",1)
$i=1
$j=1
While 1
   _FFConnect()
$line =FileReadLine($file,$i)
$line1=FileReadLine($file1,$j)
If($line=="END")Then
      Exit
   EndIf
  
_FFTabAdd()
MouseClick("left",229,43,1)      ;For opening URL
   send($line,1)                          ;URL Open from txt file
   Send("{ENTER}")                   ;ENTER for URL
   ;Sleep(1000)
   _FFLoadWait()                       ;Waiting for Page to be Load
MouseClick("left",239,483,1)    ;click Add New Post
_FFLoadWait()                    ; Waiting for page to be loaded
MouseClick("left",526,537,1)    ;clicking on cat drop down
sleep(1000)
send($line1,1)                           ;sending category from another file
MouseClick("left",530,639,1)     ;clicking Next Step
_FFLoadWait()
MouseClick("left",650,507,1)    ;clicking empty area for activating page
Sleep(1500)
Send("!z")                         ;robo form fill submit
_FFLoadWait()                          ;waiting for submission and page redirection
MouseClick("left",367,627,1)    ;Click ON Text Field
sleep(15000)                             ;waiting for providing info
MouseClick("left",508,476,1)    ; CLICK FOR GO BACK  submit
_FFLoadWait()
sleep(1000)
_FFConnect()
If _FFIsConnected() Then
    
    _FFLinkClick("GRAND EXPERIENCES offers (abc123)","text")
    _FFLoadWait()
    Sleep(1500)
   EndIf
    Sleep(1500)
   MouseClick("left",414,45,1)    ;copying url
    Send("{CTRLDOWN}a{CTRLUP}{CTRLDOWN}c{CTRLUP}{down}")
    Local $text=ClipGet()
   $line3=FileWriteLine($report,$text)


$i=$i+1
$j=$j+1


WEnd