Welcome to the SitePoint Community Forums! I wonder how you found out about this place...? It's nice to have a new person who's just starting their adventure in the Web design / development industry. You're venturing out in to a sector of the IT industry that could possibly be the most exciting thing to happen in the industry, and at just the right time too.
I agree with the others who have posted in this thread, but I'd just like to add a few things of my own as I'm sure it'll help. The more responses the better, right?
From the looks of the Website code developed through Serif - Yes, it will hinder your Websites search engine ranking. However, it's important for me to add that your search engine ranking won't be determined solely from the code developed by using Serif, it will just be a part of a few different factors that will hinder your Websites search engine ranking. The code behind a Website is an important aspect though.
I don't blame you, I would be too. The beauty of developing a Website using Web standard languages such as HTML and CSS is that you can use them in almost any text editor or Website authoring application, so you don't need to be tied down to any application. I actually strictly use Windows Notepad because it loads up instantly and I can begin my development immediately (although it doesn't have some nice features such as syntax highlighting, etc.) and the development of the Website is down to me, without anything getting in the way.
However, I know that I can develop my Website in Expression Web, Adobe Dreamweaver, Komodo Edit, Notepad++, and a whole load of other applications. I just choose to stick with Windows Notepad as a preference, and of course it comes built-in to Microsoft Windows operating systems, so there is no additional cost for me to even begin developing Websites.
It's funny you should say that as Adobe Dreamweaver is touted as the industry standard...For novice Web designers / developers. Most professional Web developers will not use Dreamweaver and choose instead a pure text editor with additional features to help them. There are professional Web developers that use Dreamweaver because it is their preference, but I wouldn't agree that it is an industry standard. When I first downloaded Dreamweaver, an illegal copy I admit, I didn't have a clue what I was doing, I was pressing buttons here and there trying to figure out what it does, but it didn't help me out. I know how to use Dreamweaver today, but I no longer have a copy of it and I certainly wouldn't buy a copy for the price tag, nor would I recommend you buy it, although from your experience, I don't think you will. :lol:
Do not feel that you should use or buy a copy of Dreamweaver because you believe or have been told that it is the industry standard. I encourage you to ignore that statement. Instead, go with what you feel will be the best fit for yourself, and for your future in this industry.
Hand coding Websites in a text editor similar to that of Windows Notepad is the best option, although you can use other much more advanced text editors, such as Notepad++ which will be very helpful to you, especially in the beginning.
I personally recommend that, if you're using a Microsoft Windows OS, you open Windows Notepad and start developing a few plain HTML Web pages. Understand the importance of the markup language and how it works. It's perfectly acceptable to have plain-jane Web pages as long as the content appears in a manner in which the audience can view and access it. Then open another instance of Windows Notepad and start creating a cascading style sheets file. Link it up in the relevant Web pages and you'll then be able to understand the power of CSS and how it is just a layer on top of the HTML files.
Lastly, I have a few book recommendations for you. Firstly I would recommend [Getting StartED Building Websites (you can also read my review on that book on the same page, I hope that helps). Secondly I would recommend SitePoints own [URL="http://www.amazon.co.uk/dp/B00486U4QC/"]Build Your Own Web Site The Right Way Using HTML & CSS, 2nd Edition](http://www.amazon.co.uk/dp/1430225173/) which you can purchase for the Amazon Kindle (or Kindle for PC application) at an amazing price!
If you've got any more questions then ask away!