Cannot set properties of undefined (setting 'count')

[AliRezaBeitari]

I'm using the latest version. When I load a file, it gets stuck at the Loading... popup. When I check the browser console, I can see this error:

Uncaught TypeError: Cannot set properties of undefined (setting 'count')
    at updateHeaderSortCount (jquery.tablesorter.js:419:14)
    at HTMLTableElement.<anonymous> (jquery.tablesorter.js:611:7)
    at HTMLTableElement.handle (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:26157)
    at HTMLTableElement.eval (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:23905)
    at Object.trigger (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:25523)
    at HTMLTableElement.eval (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:28478)
    at Function.each (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:8461)
    at init.each (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:1089)
    at init.trigger (eval at <anonymous> (jquery.js:11:1), <anonymous>:1:28454)
    at Object.success ((index):72:27)

Here is the line it breaks at:

$("#function_table").trigger("sorton",[[[sortCol,1]]]);