error 500 when updating member information

I'm pretty new to Joomla and was hired to work with an existing website. The problem that has come up is when a member logs in through the front end and attempts to update their profile, they receive a "500 internal server error". The error message reads, "The server encountered an internal error or misconfiguration and was unable to complete your request."

The changes show up on the backend, so the update works but the error message shows up anyway.

I contacted the hosting company to see if they had any ideas of what could be causing the problem and they found that the update script is looping upon execution.

Any ideas on how to fix this?

I just updated Community Builder in hopes that would fix the issue, but no luck. I am running Joomla Version 1.5.25

The website is www.cachecanada.org

Thanks

Any possibility to update Joomla from 1.5 to the current version?

That suggestion has been taken to the board of the organization. They are apparently discussing it. I'm hoping that I can solve this problem in the meantime.

When I was searching the FAQs I came across the idea that it could be a PHP memory error. I ran the test found here: www.joomlapolis.com/support/tutorials/95-installation/18200-checking-your-php-memory

And I got this back: Fatal error: Allowed memory size of 100663296 bytes exhausted (tried to allocate 100663297 bytes) in <span>/</span>home<span>/</span>cachecan/public_html/phpmemtest.php on line 15

You can see the results here:
www.cachecanada.org/phpmemtest.php

Their response was this: "As far as I can see your script is reaching global execution memory limits. Please note that your account is situated on a shared hosting server and we cannot change limits per user request. For more information about current PHP configuration and limits, please open this link:

cachecanada.org/phpinfo.php

In order for the issue to be fixed I can suggest you the following options:

1) To contact a local developer and ask your application to be optimized.
2) To upgrade your account"

I am on a shared server. Does Community Builder need a dedicated server? Or is this a corrupt file issue?

I'm running CB on a shared server with only 100mb of RAM, your 96mb should work fine.
Interesting -
If I can find time I'll dig around and see if there's some incompatibility with your hosting setup (if possible).

That would be fabulous.

Would it help to attach the log from the strace command that the hosting company used to determine that the update script is looping upon execution? (It's pretty long)