Wizard Screen goes blank after multiple changes

This is my fist attempt to use CSS Menu writer for a long time due to a bug that caused the wizard screen to go blank after multiple changes to the theme in past versions. Looks like the problem still exists in V2.0.5.

Here's the steps I use to create the bug every time.

Create a 2 tier SQL menu
Go and create a custom theme.
Change Box, Type and Design, Change line widths to none
Return to Box Tab and bang blank screen.

I have deleted Dreamweaver CS5 cache after install
Tried creating a new CSS Menu and removed all directories from previous attempts.
Nothing i do works, It's OK as long as i don't try and change every aspect of the menu under the the options. Also once the screen goes blank the buttons to save stop working

Screen dump attached of blank Wizard

P.S: Also if I have a top menu box height of 55 with a gradient background how do i get the text to align horizontal Centre and Verticle Centre, None of the Block properties seem to change the final layour. At present only option is to centre text but it remains at the top of the box.