Can't draw line from intersection point.

Hello,

I've been searching for answer everywhere, the thing is I can't explain it in english well enough to find the solution, I gotta say sorry in advance if this problem is too basic! 

I was trying to draft lines over the grid lines I already have.
Instead of normal drafting, this little-yellow-icon appear when I selected the starter point, then force me to draft 90degrees from the original line.

pic: http://imageshack.us/photo/my-images/233/picture1jz.png/

Please help! I hate copy and paste lines all the time :(

Thank you so much.
I love draftsight :)