The Kunena team has announce the arrival of Kunena 6.3.0 [K 6.3.0] in stable which is now available for download as a native Joomla extension for J! 4.4.x/5.0.x/5.1.x. This version addresses most of the issues that were discovered in K 6.2 and issues discovered during the last development stages of K 6.3
Question
Problem in Attaching file in Chrome and IE 6
There are issues involving Google Chrome in K 1.6. These may require the involvement of Mootools 1.2.5. Discussions are occurring now with the Joomla development team to ascertain if (or when) MT 1.2.5 might be available for J! 1.5.
I'm sorry if I can't give you a specific answer to this question. I'm sure that there are a few other people who will find themselves in this situation.