Hard to give specific answer without seeing your html but I've had a similar problem before and i think its actually your UIWebview thats actually scrolling and not the scrollview. somewhere on the page in the UIWebview html you will most probably have oversize content. THe webview naturally wants to scroll. In my case it was a long URL in a paragraph of text. I have also seen this happening vertically.
You need to find the container element to your oversize html and set the overflow to hidden in the css. It may be that this is the body tag or the html tag in the html or you need to wrap your content.
ie;
Overflowing text
Failing that you may have to play with the following tag
Or set the container div to width:100% & height:100%;
