Well I think what you wanted to do was:
This code differs from yours by a character. Its the PIPE command and it is accomplished by doing a shift backslash. You want to pipe the contents of the locate sommand into grep to get something useful.
locate network | grep howto
Not sure why but it seems as though bash is interpretting those as 2 seperate commands with nothing delineating them. Kinda wierd. This is of course not concrete, I may very well be wrong with this so, please if someone else knows, chime in.