urgent-sporadic hang in autoit script

hi, I am using a simple script to clean up chars in another app. The functions used are winactivate, send, controlcommand -none of which should be waiting but yet I have an OCCASIONAL hang where the script just does not complete execution and the target app too wont respond to any events.

Just to be clear, its not that the script hangs every time its invoked but it locks up once in a while.
Here is the script:
;clear text if any
if WinActivate("MP")==0 Then
   exit 1
EndIf
;get to the panel
Send("!o")
Send("a")
Sleep(1500)
;v26Jan13. clear and activate Capture app
Send("{BS}{BS}{BS}{BS}{BS}{BS}{BS}{BS}{BS}{BS}{BS}")
Sleep(1000)
WinActivate("Capture")
exit 0
--------------
I really need to resolve this ASAP so any pointers appreciated. I run on win XP SP2