Your on that stupid arrow thing. Just reset all your tools to do this read on.
Select the line tool, then click the down arrow, in the top left corner of the toolbar that has come up beside the line tool icon.
Down comes a list of junk on the right hand side of that drop down menu there is another arrow pointing right. Click it and out pops another menu - look in that menu for Reset Tool / Reset All Tools I think.
Done, Bam, Whammo!!