large matrices

edit

when I write

matrix(CDF,dim)

with dim <=19 the result is a dim times dim matrix with all zero elements. If on the other hand dim is equal or larger then 20 then, in the command line I get the outout

20 x 20 dense matrix over Complex Double Field

in the browser with the the Typeset button selected I obtain a large matrix with all zero elements in the pretty_print style, but in the browser without the Typeset selected I get the following error message

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "_sage_input_31.py", line 10, in <module>
    exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8 -*-\\n" + _support_.preparse_worksheet_cell(base64.b64decode("ZGltPTIwCm1hdHJpeChDREYsZGltKQ=="),globals())+"\\n"); execfile(os.path.abspath("___code___.py"))
  File "", line 1, in <module>

  File "/private/var/folders/Xg/Xg29Zoq9FceX+ITv5eX+u++++TU/-Tmp-/tmptw3cJO/___code___.py", line 4, in <module>
exec compile(u'matrix(CDF,dim)
  File "", line 1, in <module>

  File "matrix0.pyx", line 1729, in sage.matrix.matrix0.Matrix.__repr__ (sage/matrix/matrix0.c:9374)
  File "/Applications/sage/local/lib/python2.7/site-packages/sage/misc/sageinspect.py", line 1915, in sage_getvariablename
for frame in inspect.stack():
  File "/Applications/sage/local/lib/python/inspect.py", line 1054, in stack
return getouterframes(sys._getframe(1), context)
  File "/Applications/sage/local/lib/python/inspect.py", line 1032, in getouterframes
framelist.append((frame,) + getframeinfo(frame, context))
  File "/Applications/sage/local/lib/python/inspect.py", line 1007, in getframeinfo
lines, lnum = findsource(frame)
  File "/Applications/sage/local/lib/python/inspect.py", line 528, in findsource
if not sourcefile and file[0] + file[-1] != '<>':
IndexError: string index out of range

Is it only my problem?

('Sage Version 5.9, Release Date: 2013-04-30', Firefox 20.0/Safari 5.1.8, osx 10.6.8)