Last update: 2013-01-20
Magento Compiler feature should be disabled on any changes in loaded Magento classes, in other words, you need to disable Magento Compilation every time before installing new extension or initiating upgrade/downgrade/installation or removal of any Magento module.
To disable Magento Compiler you can use one of the following methods:
- delete includes directory or rename it to any other name (_includes.unused for example):
ftp :~> mv ./includes ./includes.unused
- Flush Magento cache