The actual problem is that mirc is inconsistent regarding the order of
index and
filename in different scripting elements that have to do with dialog icons. The details are described
here.
Btw, icon indexing is zero-based, so if the icon #1 exists, #0 would definitely exist too
uicn_renegade: I would advise against using variables in icon definitions, for now. The workaround is pretty simple too: just use the on dialog
init and
close events to load/save the icon yourself.