[TYPO3-templavoila] Fatal error from value in tx_templavoila_flex

[Neil Bertram]

Hi,

One of our clients is having periodic problems with their site because 
of values cropping up in the tx_templavoila_flex field of the pages table.

Occasionally (not sure why) we get entries like:
<numIndex index="5" type="NULL"></numIndex>

These cause PHP to throw a fatal error when they try to edit the page in 
the page module:

PHP Warning:  key() [<a href='function.key'>function.key</a>]: Passed 
variable is not an array or object in 
/usr/share/typo3/4.0.0/t3lib/class.t3lib_transferdata.php on line 597
PHP Fatal error:  Cannot use string offset as an array in 
/usr/share/typo3/4.0.0/t3lib/class.t3lib_transferdata.php on line 598

Does anyone know what causes this to happen? My current solution is to 
manually edit the flexform XML to remove such entries whenever they 
complain, but it's becoming a daily event now!

We're running standard TYPO3 4.0 on PHP 5.1 on Linux, TemplaVoila 1.1.0


Many thanks,

Neil