CHeckout Page Special Characters cause HTTP 500 Server error

[split63]

All of our product titles are just simple text. We still get this error from time to time with no idea what the issue is.

[dgent]

Apparently you're the expert. Let us know the solution to your unique problem when you're ready to share.

From this very site....

PHP errors Sometimes when a PHP script encounters an error, either due to a timeout or a syntax problem, or something worse like a logic problem, it *might* trigger a 500 Internal Server Error. It may not always do so, but it may.
In such cases, if you use the Zen Cart debug logs to review PHP errors, you might discover the cause of the problem there.

[split63]

Unfortunately, the log files do not appear to have any information on this error.

[split63]

Looking in our logs, we found errors affecting our FedEx Web Services plug in. The errors were related to UTF-8
For example, "Encoding: string 'S\xfc...' is not a valid utf-8 string in...."

Though there are no specific log entries, I'm told that this UTF-8 issue is the source of the occasional Server 500 error as well.
Zen V1.5 now uses UTF-8, but only for new installs.
So how would I go about supporting UTF-8? Are there any issues with changing to UTF-8? For example, will I just then receive errors that strings are not valid for....?

Thanks,