Using Cron to run a python program

[vagrantbrad at yahoo.com]

I'm using python 2.4 running on Fedora Core 4.  I have written a python
program called ipscan.py that checks the external ip address of my
cable internet connection, and on change, will update the dns records
at my dns provider, zoneedit.  So basically, I've setup dynamic dns
using python.  Once the ip compare and/or update is complete, I log the
results to a text file called update.log.  When I run the program in a
bash shell with the command "python ipscan.py", the program runs fine
and the results are appended to update.log.  When I run this program as
a cron job under the root user with the previously mentioned command,
the program runs without errors but does not append an entry to the
log.  The permissions on the update.log file should not be an issue
since I'm running the cron job as root, but I've given root write
permissions just to be safe.  What would cause the logging to work at a
command prompt but fail in cron?  I'm not getting any errors in the
cron logs or /var/spool/mail/root.

Thanks for your assitance.