It could be two things:
- Check your code in "code view" -- there could be pieces of an editable region's coding floating out there without your knowing it. Dreamweaver doesn't always delete things efficiently. It's always best to check your code, just to make sure. You can also validate your code at http://validator.w3.org to make sure there are no other errors, such as missing closing tags.
- A table is only as tall as its content, unless you've specified a pixel height. If you're deleting a row, the table will shrink to accommodate the loss of content. No matter if you've got the table locked in a template or not, it will collapse. Look at your coding to see if you've a) specified a height, or b) have an undetermined height.
If you're wanting a specific height, and then have the table grow to accommodate text exceeding this height, you'll have to apply a css style to the table.
<table style="min-height: 800px; overflow: visible;" >
* My screen resolution is set at 1680x1050
* I'm accessing your site through a T1 line
* I'm probably viewing it using Firefox (unless browser is specified)