[Open Babel] "Any ideas why this doesn't work..." (babel: cannot write output format!)

[JP <jea...@in...>]

Yo OpenBabels,

Any ideas why the following

> babel test.mol2 test.sdf
babel: cannot write output format!
Open Babel 2.3.0 -- Nov  1 2010 -- 11:33:23
Usage: babel [-i<input-type>] <name> [-o<output-type>] <name>
Try  -H option for more information.

test.mol2 exists, is correct,and the same command line with the same
files work on another machine.

Many thanks...

Jean-Paul Ebejer
Early Stage Researcher