DCC/mIRC was never designed for "large files" - you've tried Invision script so I assume you're using mIRC to file share? This is not the purpose of mIRC and if you're downloading a file such as movies (which are hundreds of megabytes usually) then it's illegal (Same goes for mp3s, software and so on.)
Perhaps try a virus scan (see this thread
) or use the Search feature for 'freeze', other people have had similar issues. Expand to 'All Forums' amd 'All Posts' for best results. If you do the former make sure you use more than one virus scanner/trojan scan as no *one* can pick up everything.
Just a note, there was no version 6.13. It went from 6.12 to 6.14
- 6.13 was a virus-infected mIRC DUMMY client. If you downloaded it (and you're not just making a mistake) then definitely scan your system.