Move Dim $arrGroups[0] to the main part of the script
If a varaible is dimmed in a function, scope of the variable will be limited to the function

code:

;Kixtart.kix  
Dim $arrGroups[0]
call myfunctions.udf  
CreateArray()  
UseArray()
;End Kixtart
_________________________
? getobject(Kixtart.org.Signature)