[BUG] mc edit Floating point exception 4.6.0pre1

[Ury N.Stankevich]

this steps cause <Floating point exception>

open any file in internal editor to edit
set tabulation step to 0
press <TAB>

and one more... 
i have trouble in use ftp capabilities under user:
when i connect to ftp server - i see notning on panel, and in tips
string i see 'ftpfs: failed; nowhere to fallback to'
while under r00t - all ok.
this my mistake or bug?

__Ury