I think I found a bug in ACAD FS, earlier today I left my instance of FS running for a long period of time, say, 4 hours.
And now after starting the app again, I can't seem to draw straight lines anymore with the Line tool when I used to be able to. You know, it would automatically click to 0, 45, 90, 135, 180, 225, 270 and 315 degrees when it's near one of those values, but now it's not doing that anymore. It just draws lines to wherever I click and eye-balling a straight line is not good for floor plans since dimensions will come out wrong. I would use Shift to draw a straight line but I need 45 degree angle straight lines also.
I've played around with the very few settings that you get with FS and nothing worked.
Note: I do have the student edition of AutoCAD 2011 installed, would that affect FS???
Does this problem still exist after shutting down Freestyle and then launching again? Also check to see if the "Use alignment guide" checkbox in the My Setting palette is checked. This controls the 0,45, 90, etc... alignment guides.
Please let me know if either of these works for you,