I am a long time Dreamweaver fan, starting version 1.0, and it is one of my favorites by far. However, tables in DW are one of the few areas that the program sometimes frustrate me.
First of all, I would not use % values for hieght and width. Unless you really want a site to expand and contract, % is not good. For most sites, pixels allow you more control on design. for sites that have paragraphs that people are to read (articles for example), % is bad bad bad.
A basic rule of typography is to not have lines of text be too long. If they are, people have a hard time finding the next line of type after they get to the end of one. That is why books fill each page, yet wider formats, such as landscape oriented books magazines, newspapers, etc. use 2 or 3 colums of text. So on a site, % can make the text too long when viewers have a very wide browser window. The only time I use % is when I want to center my entire page in the browser window (see my site at
www.phelpsinteractive.com for an example). I make a table that is 100% wide and 100% tall, with the alignment inside the table (just click in the middle of it) set as middle and center, then I put my sites content (such as the Flash file at pehlpsinteractive.com) in the middle. that way, as a person resizes their browser window, my site stays in the middle.
Here are the requirements for every table (DW won't always autmatically put the values in, watch the HTML and edit the code if you have to.
1. you need width and height values for each table you build
2. you need width and height values for every table cell
3. the sum of the widths of all table cell in a table row must equal the width of the table.
4. the sum of the heights of all table cells in a table column must equal the hight of the table.
Now, there can be 3 states of each cell
1. empty 2. text 3. graphics
Text and graphics are usually not an issue. Images, especially ones that are the exact hight and width of the cell it resides in, helps keep the size of the row and colum that is risdes in. Text can do this too.
Empty is the issue. I usually make a small photoshop file that is pure white. You can make a 1pixel x 1pixel image, but I like to make one that is 10pixels x 10pixels or so. Make it all white and save it as a GIF with white transparent. Many talk of a Transparent GIF, and this is what we are making here. Place this in a cell that is totally empy. Then select the image in the table cell and in the Property Inspector, type in a new hight and width using the values of the cell it is in. This forces that cell to maintain the hight and width just like any image (like I mentioned above). So, you basically have to make sure every sell has sometihng in it. If you leave a cell or 2 empty, it sometimes can be ok (depends on total number of cells), but if you preview a table with very little content or no content at all, you might get some funky results.
If you have Adobe ImageReady (bundled with Photoshop since Photoshop version 5 or 5.5) then I recommend building any graphic intensive tables in there. Use the slice tool to draw you table cells then export the HTML file to your sites root folder and tell it where to export the sliced images. Open this HTML in Dreamweaver and preview it. I bet money that it previews good. I've never had major issues this way. Of course later editing might present gaps or whatever, but just follow the instructions above. The more content you have in a table, the less likely you are to have problems with it.