Error with AngularJS ng-hide

Error with AngularJS ng-hide

Apparently i don't fully understand how Angular's ng-show directive
interacts with the $scope. I'm trying to hide an element when an array is
empty. my html is as follows:
<h1>Tabs</h1>
<ul ng-hide="tabs.length == 0">
<li ng-repeat="t in tabs">
<img src="{{t.thumbnailurl}}" />
</li>
</ul>
tabs is this:
Array
0: Object
$$hashKey: "01H"
created: "2013-08-20 20:15:00"
thumbnailurl: "https://s3.amazonaws.com/xxxxx"
__proto__: Object
1: Object
$$hashKey: "01J"
created: "2012-07-09 23:26:49"
thumbnailurl: "https://s3.amazonaws.com/xxxxx"
__proto__: Object
length: 2
__proto__: Array[0]
When i load my page, ng-hide throws the following exception in the console
stating the anonymous function has no method 'trim'. Obviously Angular is
puking somewhere in the internals.
TypeError: Object function () {
// If the string looks like an identifier, then we can return it as is.
// If the string contains no control characters, no quote characters, and no
// backslash characters, then we can simply slap some quotes around it.
// Otherwise we must also replace the offending characters with safe
// sequences.
if (ix.test(this)) {
return this;
}
if (/[&<"\/\\\x00-\x1f]/.test(this)) {
return '"' + this.replace(/[&<"\/\\\x00-\x1f]/g, function (a) {
var c = escapes[a];
if (c) {
return c;
}
c = a.charCodeAt();
return '\\u00' +
Math.floor(c / 16).toString(16) +
(c % 16).toString(16);
}) + '"';
}
return '"' + this + '"';
} has no method 'trim'
at watchFnToHumanReadableString
(http://b.gro/campaigns#/tabs/23402:706:30)
at Object.$delegate.__proto__.$watch
(http://b.gro/campaigns#/tabs/23402:735:28)
at
http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:13829:9
at nodeLinkFn
(http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:4406:13)
at compositeLinkFn
(http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:4015:15)
at publicLinkFn
(http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:3920:30)
at <error: illegal access>
at Object.Scope.$broadcast
(http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:8307:28)
at
http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:7463:26
at wrappedCallback
(http://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.js:6846:59)
<ul ng-hide="tabs.length == 0" class="ng-scope"> angular.js:5754
According to the ng-hide/show docs, this directive should be pretty
straight forward and accept truthy/falsy statements that are passed to it.
I'm just not sure what i'm doing wrong here....