[Lynne]

The template isn't cached because it isn't $THIS_SCRIPT, it should be simply THIS_SCRIPT.

And what did you add to the SHOWTHREAD template to get this code/template to display? Since all the posts are added by this single line in that template, I really can't see how you think what you are doing is going to add something between the first and second post:

{vb:raw postbits}