looks like there's a couple things, I don't think that would even compile: comparing a map<int, vector<int> >::iterator to an int inside your loop doesn't seem safe to me. As well as not declaring the map type for your iterator.
anyway, see if this is a good starting point:
map<int, vector<int> > my_map; //I assume these are global or in a class, as you had it
map<int, vector<int> >::iterator it;
void erase(int num)
for(it = my_map.begin(); it != my_map.end(); it++)
if((*it).first == num)
I think that's what you were going for, hope that's helpful