Here is my input file: Width, pixels: 200 Height, pixels: 337
And my command:
/usr/local/bin/montage -debug exception -size 240x240 -label %f '/home/xxxxx/public_html/test/images/footsteps7.jpg' -frame 6x6 -thumbnail 140x140 /home/xxxxxx/public_html/test/images/tmp_thumb.jpg
And my result: Error code=> 0
Array
(
[0] => 13:15:40 0:01 0.170u 6.2.8 Exception montage[13506]: decorate.c/FrameImage/209/Exception
[1] => frame is less than image size `/home/xxxx/public_html/test/images/footsteps7.jpg'
)
The resultant image has no frame and is 140x158

And, note the response code is "0"; seems like it should be something else.