Thanks for your bug report. I have not been able to reproduce this issue here so far. Please type the following command into mIRC and post your results:
Code
//echo -a $os $version $beta $md5($mircexe,2) $file($mircexe).sig $alias(0) $script(0) $dll(0) $com(0)

In order to help track down this issue, please also try the following:

1. Install a clean copy of mIRC in a new, empty folder, with no scripts or addons.
2. Run mIRC.
3. Create several variables, eg. using a simple script:
Code
//var %n = 1 | while (%n < 10) { set %v $+ %n %n | inc %n }
4.Add this code to a remote script:
Code
ON *:EXIT:{ .save -rv $+(",$readini(mirc.ini,rfiles,n1),") }
5. Exit mIRC.

If you follow the above steps, with a clean install of mIRC, do you see the issue?