For those interested, even though it's not a supported theme, zpBootstrap does not work with 1.6. In checking the source HTML of the resulting page once activated, it stops writing the page in the head at ``` <title> ```
From basic testing, it is the call to getMainSiteName() that seems to cause failure. Is there another call that will do the same thing for 1.6?
For me, as I have one site and the whole thing has one name, I just swapped this out with gettext('MySite'sName') and that seems to function correctly.