tfoot causes colunm.nTf undefined and alphanumeric sort

pixelwiz

Hi, I'm very new to using this plugin. I've been able to get it to work successfully on a stand-alone basic test.

However, I am trying to use it to replace tablesorter 2.0. And so far on the first page I tried to do it, I've ran into 2 problems:
1. My table has a tfoot with colspan="9" spanning all the columns. I actually display a form in the tfoot. I could potentially move it into its own div, but I should be able to keep it in the tfoot. The actual error I get is on line 1751:
TypeError: column is undefined
column.nTf = cells[i].cell;

If I remove the tfoot, the error goes away. Not sure what the best and proper way is to fix this.

The second issue has to do with sorting. One of my columns in the table has data that looks like this:
<a href="group_edit.cfm?eventid=5097&groupid=23451&round=2">Group 14</a>

So it's a link with the word Group and a number. When it sorts, I get this:
Group 1
Group 10
Group 11
...
Group 19
Group 2
Group 20

What do I need to do in order to have Group 2 be placed after Group 1 in the sort, not after 19?