Can you advice me how to go about, following mail received from our webhosting company

This issue is related to memory allocation for PHP file execution. You can increase the memory limit using the php.ini file. Place this php.ini file in the directory which contains the php file for which you are encountering this error.

You can add the following line in the php.ini file
memory_limit = 12M (12M is just an example)

You will need to experiment with the value that is right for you depending on which modules you are using.

Our server has a maximum limit of 40M and hence you can increase the value within this limit. Kindly consult your web developer to integrate this file and the settings on the itsybitsy.in package.