Ctrl-C/D/E/F work just fine, unless you managed to remove the hotkeys for those in MUICON's settings. Window close gadget just iconifies the window if it cannot abort the running command, by the way.

One problem you might be seeing is that ixemul does not forward those signals to vforked subprograms. Those can still be aborted with TaskManager. This is an issue unrelated to MUICON.

Btw. not that I mind you updating perl, but wouldn't it be less work to just fix the perl scripts to work with older perl? (yeah, I'm lying to myself now, I know that perl is a "write once, change never" language).