"Could not Open" error for COA, Extensions and themes etc

I had installed FA on Mint 16 (Ubuntu13.10) and could never activate or install COAs, extensions or themes etc. I could however access all these functionalities using the same FA version in Ubuntu 12.04 as well as on Mint 14 (Ubuntu 12.10). I narrowed down the problem to php5 version and had to downgrade it to php5.4.9 using this link.

http://stackoverflow.com/questions/19733422/downgrade-php5-to-5-4-9-4ubuntu2-2-in-ubuntu-13-10

With php5 version 5.4.9, everything is working fine on Mint16 (ubuntu13.10). I stumbled upon info that some functions of mysql_* family are deprecated in php5 v5.5 and maybe even removed in v5.6, is that root cause of the problem. Is it that FA is not compatible with php5 v5.5?

Can someone help? Or assure that future releases of FA will be compatible with stable and recent versions of PHP5 and therefore Ubuntu?
---Neelesh Viswanathan