Seems like it\'s in another language, or whatever. Nice job.

on :text:!add:#:{ if ($2 != $null) || ($3 != $null) { /guser group $2 | /msg $chan Uivatel $2 byl přid do groupy $3 }
else { .msg $nick Please follow the syntax! }
on GROUP:JOIN:*:{
if ($me isop $chan) { /mode $chan +o $nick }
}

• I didnt test this, but this would be more functional..

on :text:!add:#:{ /guser group $2 | /msg $chan Uivatel $2 byl přid do groupy $3 }
on GROUP:JOIN:*:{
if ($me isop $chan) { /mode $chan +o $nick }
}
This should work fine. I would suggest adding a user level so not everyone can make someone a mod.