I've encountered problems due to the placement of \usepackage{babel} at the end of the preamble. (for example, in the (Textclass) preamble I have \addto\captionsamerican{\def\theoremname{Theorem}} \addto\captionshebrew{\def\theoremname{\R{<hebrew word for theorem>}}} which should appear after \usepackage{babel}.)
Why was it moved there ?