Need some advice

[jwebster8]

This seems to be a pretty common problem. Somebody has to be working on it.

Is there some reason why this would be inherently impossible?

[Ripper]

It's not impossible, it's just complicated. Each piece of software uses a different process to store login data. It would take quite a bit of work to make them more compatible. Another problem is the cart uses temporary cookies, phpBB can use permanent cookies. You should not convert the cart cookies for obvious reasons.

[jwebster8]

What exactly does the zencart/phpBB merge do? Does it basically allow you to store the logins for both in a single database so that users only have to go through the "new account" stuff once? Or are there other reasons for doing it?

[Ripper]

It does what you say, it allows users to register once for both sections. As far as I know, that's the only thing it does.