This question about Using an extension: Asked
MathMode fails with missing value in Carp.pm
Foswiki 1.0.9, but also had this problem on earlier versions.
Stuff put into <latex> tags disappears, and the only thing I see is in my apache logs:
view: Use of uninitialized value in die at /usr/lib/perl5/5.8.8/CGI/Carp.pm line 314.
I'm guessing that something is not getting passed correctly to Carp.pm?