this is actually a bug of CakePHP. Lemon8 comes with an older dev version of CakePHP 1.3 which used the E_NONE constant. I looked in the PHP source code and it seems that E_NONE never existed. There is a PHP bug that indicates that E_NONE was (wrongly) contained in the PHP documentation but never implemented (see http://bugs.php.net/16330
As rcave said, you can solve this problem by replacing E_NONE with the number "0" (or any other valid E_* constant) in the source code.
We won't provide an "official" patch for this as we no longer actively develop Lemon8. All Lemon8 functionality will be directly included in our applications (starting with OJS) and the Lemon8-functionality will also be usable stand-alone as a programmer's library to be included in your custom code.
Please have a look at http://pkp.sfu.ca/wiki/index.php/Lemon8-XML_Roadmap
for our plans re Lemon8.