irefox add-on not working after browser update

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We have a Crossrider app that we've been using for a few months on Firefox and Chrome. The app id is 65981 (for Crossrider support). It worked fine until recently (we are using Firefox v36.0.4) and it's still working on Chrome. Nothing was changed in the source code, so I'm guessing it's a compatibility issue due to one of the latest Firefox updates.

As soon as I open the add-on I get a lot of warnings in the console:

SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:7:24786
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:7:26521
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:8:13810
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:8:15975
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:8:20231
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:8:20319
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:8:26137
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:9:11153
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:9:11206
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:9:12076
TypeError: variable D redeclares argument browserAction.js:84:5789
ReferenceError: assignment to undeclared variable $jquery browserAction.js:2:4
ReferenceError: assignment to undeclared variable $jquery_171 browserAction.js:2:4
ReferenceError: reference to undefined property f.valHooks[this] browserAction.js:7:31691
ReferenceError: assignment to undeclared variable appAPI browserAction.js:48:33
ReferenceError: reference to undefined property appAPI.platform browserAction.js:48:12693
ReferenceError: reference to undefined property b.platform browserAction.js:60:0
The Components object is deprecated. It will soon be removed. browserAction.js:66:0
ReferenceError: reference to undefined property Components.classes browserAction.js:66:14764
ReferenceError: assignment to undeclared variable currentUrl browserAction.js:66:17473
ReferenceError: reference to undefined property appAPI.__should_activate_validation__ browserAction.js:96:0
SyntaxError: test for equality (==) mistyped as assignment (=)? browserAction.js:2:17047
TypeError: variable e redeclares argument browserAction.js:2:18775
TypeError: variable t redeclares argument browserAction.js:2:18788
ReferenceError: reference to undefined property f.event.triggered browserAction.js:8:1980