It has been a while since i've done asp vbscript... I just recognized that it was a scoping issue and did a few google searches to find the public declaration mentioned... I don't think updating the sub to public would matter... it is the variable in the sub that has the scoping problem.
Yes, the string building code is very nice. It was the major feature in v2, and it makes a big difference. I remember how clever I thought we were when we added it so many years ago now.
In v4 (php only) we took it even one more step and allow you to actually build up the string in a separate page and we get the string from there without ever having to build it up in code at all.