May I suggest you accumulate the tank names/labels in a Python list and then concatenate them with a string.join().
David and I spoke on the phone, the source of most of these problems was that the label was actually named something slightly different…
At any rate, I also suggested using Lists as a more flexible way of dealing with the names.
I did a search and randomly picked a list tutorial, it looks like it’s a fairly good introduction:
Wow, this thead was confusing to catch up on. It seems to be resolved, but I’d just like to suggest something…
When debugging an unruly script, the print keyword is your friend. When you print things, they go to the console (Tools > Advanced > Console).
This helps you see what the script is doing while its running so you can fix it.