Any problems between eCart5 and the DreamWeaver HTML5 pack update?

For a couple months I've been working on a site using eCart and DreamWeaver CS4.

I am new to all this and just now learning how to use it. I've remade the cart from scratch a number of times, but it's always worked fairly well until today.

I originally had the eCart, DataAssist, SecurityAssist and Universal email extensions installed.
Last week, I installed all the other extensions, starting with the Cookie Toolkit.

On Friday, I installed an update that was available for Adobe DreamWeaver: the "HTML5 update pack". I can't remember if I installed any extensions after I installed that DreamWeaver update, but I do know that I had previously disabled SecurityAssist because of the bug that conflicts with the Cookie Toolkit, and I have since re-enabled SecurityAssist (which might be similar to installing it?).

Today, I backed up my site files, deleted the 3 checkout pages, and ran the Checkout Wizard again. It did create the 3 files, but they had a *bunch* of problems.

First, each one of them repeatedly redirected to the viewcart page. After manually comparing the code to the old pages, I finally found that the function "$cart->GetContent()" had been inserted in between the 2 redirect functions, instead of before them. I manually moved it before them in all 3 files, and the redirect issue cleared up.

I then had a problem on the checkout_success page where I was getting a warning about "headers already sent". I eventually found that the entire section of code responsible for sending the confirmation email was moved way down in the page. I moved it up to match the old pages and then the error went away.

There were several other bits of code that I had to rearrange in order to make the new pages work correctly.

I noticed in a few places the closing php tag of a given code block was on the same line as the opening tag for the next code block. The old pages from previous runs weren't like that.

Overall, it was a strange experience, since it had worked the previous several times.

If this had happened to me the first time I ran the wizard, I never would have figured out what was wrong. And I'm not sure how I can use this on other new sites where I won't have an "old working copy" to compare against. It seems that eCart is now simply generating incorrect code on my computer.

Which makes me wonder - is there some incompatibility between eCart and the DreamWeaver HTML5 update?

Please let me know if I need to provide any more information.

Thanks.