Unable to upload file due to javascript error

Firebug shows the following error:

GB_show is not defined
(no name)()dbfm.js (line 634)
[Break on this error] var listener = dbFM.addEventListener(elA, "click", function() { if (!dbFM.ve...

This is the relevant line shown:

line 634
var listener = dbFM.addEventListener(elA, "click", function() { if (!dbFM.verdir) GB_show('File Manager: Upload File',getBaseUrl() + '/dbfm_uploadit',448,640,1); });