A. Please back your site up, delete Rapid Mailer, download a fresh copy from your member area, installing it either via FTP or the Wordpress dashboard. Not only does this ensure you have the latest version, 1.7.8, this also ensures that you don't have a bad installation. You won't lose data by doing this.
Most important part is memory_limit = 256M, they can set it to higher to resolve your issue.
In the case of the upload max file size, this ensures that we can upload things like the Profit Builder Theme with no issue.
The max execution time simply means that any operations that a plugin or theme is doing will not time out. Memory simply refers to the amount of data that can be processed. Your host can make these changes, typically through cPanel, using a file called php.ini.