Thanks Shaggy
It works for Forum.asp but I get a type mismatch error in topic.asp
For x = 0 to UBound(intAllowedCategoryArray)
    If rsTopic("FORUM_ID") = intAllowedCategoryArray(x) Then
        blnForumCheck = 1
        x = UBound(intAllowedCategoryArray)
   End If
Next
If blnForumCheck = 1 then Response.Write ...etc..
I tried replacing that block of code with if instr(","&intAllowedCategoryArray&",",","&Forum_ID&",")>0 then but I got a typemismatch error on that line too.