I've been attempting to install both Crypt-Rijndael-0.05 and Crypt-Rijndael-1.02 in a test environment. I got the following error:

cl -c -nologo -O1 -MD -Zi -DNDEBUG -DWIN32 -D_CONSOLE -DNO_STRICT -DHAV E_DES_FCRYPT -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DPERL_MSVCRT_READFIX - O1 -MD -Zi -DNDEBUG -DVERSION=\"1.02\" -DXS_VERSION=\"1.02\" -IC:\Perl\lib\ CORE _rijndael.c
'cl' is not recognized as an internal or external command, operable program or batch file.
NMAKE : fatal error U1077: 'cl' : return code '0x1' Stop.

It took a bit of research and testing to figure out what was causing this error, so I wanted to post the solution I found, in case it might help someone else with this same issue. I compiled a bit of info I found on the web, along with some info brian d foy sent me via email, to come up with this.

Basically, the error it's giving is correct - 'cl' is not a recognized command.

To fix this, I installed MS Visual Studio on the server in question. I then went to C:\Program Files\Microsoft Visual Studio\VC98\Bin and ran VCVARS32.bat. This set the environment variable needed in the local folder, but didn't help me in my installation folder. So I copied VCVARS32.bat over to the installation folder I'd created for the module, and ran it there. Voila! I am now able to nmake without error.