Hmmm.. Looking at our code, we do a check to see what version of Joomla you're using in the block of code that is throwing that error. Currently, we look to see if Joomla 3.2.0 or higher is being used. If so, we do it the way that's failing for you. If it's lower, we do it an older way.
With a little research, it seems like the code works with Joomla 3.2.3 and higher, but not will likely fail with 3.2.0-3.2.2. I'm assuming you're on one of those versions.
If so, I'd first recommend upgrading Joomla. There's a few security and general bug-fixes in the 3.2.3/3.2.4 releases (or 3.3.0+ versions).
If that doesn't work, you can edit the file you mentioned. Around lines 38-51, you'll see 3 lines that look like:
if (version_compare(JVERSION, '3.2.0', '<'))
Update that to:
if (version_compare(JVERSION, '3.2.3', '<'))
That should correct the check for the proper versions.
I hope that helps, but if you have any other questions, just let me know.
Thanks,
Alex