>Index: browser/components/search/nsSearchService.js

>+        case "updateInterval":
>+          if (!isNaN(Number(childtextContent)))
>+            this._updateInterval = Number(child.textContent);

Use parseInt here instead?

>-    var sherlockLines, searchSection, sourceTextEncoding;
>+    var sherlockLines, searchSection, sourceTextEncoding, browserSection;
>     try {
>       sherlockLines = sherlockBytesToLines(this._data);
>       searchSection = getSection(sherlockLines, "search");
>+      browserSection = getSection(sherlockLines, "browser");
>+
>       sourceTextEncoding = parseInt(searchSection["sourcetextencoding"]);
>       if (sourceTextEncoding) {
>         // Re-convert the bytes using the found sourceTextEncoding
>         sherlockLines = sherlockBytesToLines(this._data, sourceTextEncoding);
>         searchSection = getSection(sherlockLines, "search");
>       }

Looks like you need to re-get browserSection here, again. This code needs refactoring, I think (though not in this patch).

>+var engineUpdateService = {

>+    try {
>+      interval = prefB.getIntPref(BROWSER_SEARCH_PREF+"updateinterval");
>+    } catch (ex) {
>+      interval = 1;
>+    }

Why fall back to 1 if the default pref is 6? No need for the try/catch, we can assume the pref will exist since we're adding it to the default pref file.

>+    LOG("adding engine to update service:"+aEngine.updateURL+','+aEngine.updateIcon);

Add spaces around operators (+)? this happens elsewhere, too.