PayPal Standard CiviContribute non-recoverable error

Using CiviCRM 1.8.alpha.10256 with Joomla! 1.0.12 on a 1and1 VPS 1 Linux/Apache/2.0.54 server
MySQL: 4.1.20
PHP Version: 5.0.4

I configured several memberships and am trying to set up a contribution page for memberships dues payment using PayPal Website Payments Standard but keep getting error when I click on Test or Live links:

[quote]Sorry. A non-recoverable error has occurred.

This contribution page is configured to support separate contribution and membership payments. The PayPal Website Payments Standard plugin does not currently support multiple simultaneous payments. Please contact the site administrator and notify them of this error[/quote]

Still get above error with "Contribution Amounts section enabled" and "Separate Membership Payment" UNCHECKED.

The contribution page only shows when I use "Dummy Payment Processor" as the Payment Processor Type.

Reproduced error in drupal sandbox with existing "Member Signup and Renewal" contribution page when changed Payment Processor Type to "PayPal Standard" and CHECKED "Contribution Amounts section enabled" and "Separate Membership Payment." Then UNCHECKED "Contribution Amounts section enabled" and "Separate Membership Payment," but still get non-recoverable error! Now get non-recoverable error with a copy and even creating new version of "Member Signup and Renewal" contribution page.

It looks like once "Contribution Amounts section enabled" and "Separate Membership Payment" are CHECKED using PayPal this can't be undone in the DB?