how can I add more ram to my iPhone?

I've never seen such an error before. Nor can I find any mention of such an error when googling.

What iPhone do you have? Settings->General->About->Model

What App is it?

Have you tried some common troubleshooting techniques?

1. A Reset may cure some bugs. Hold down the Home and sleep/power buttons until the apple logo shows up.

   If still not resolved:

2. Reset all Settings. Go to Settings->General->Reset->Reset All Settings

   If its still not resolved:

3. Restore the device as new.

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

The only reason I can see this happening is if you have an app running on your phone (foreground or background) that has a memory leak. That's a bug that would have to be fixed by the app developer.

I can't say I've ever had it happen, but it's not beyond the realm of possibility.

No. There are no user upgradeable parts in an iPhone.

Why exactly do you think you need more RAM?

Is your iPhone Jailbroken by any chance?