Cannot inject a script into a tab - google-chrome

Question

Ok, so apparently I am unable to inject an advertisement generating script into a chrome tab. Since I'm not very experienced at the chrome extensions api, I would hugely appreciate your help. So basically my main javascript file injects the script in the following way:
chrome.tabs.executeScript({
file: "inject.js"
});
so this works perfect, but the script itself doesn't seem to execute, while it works perfectly well if inserted into html directly (via 'Inspect Element' in chrome) :
var _$cmp = _$cmp || {};
(function() {
var companionId = "SK1POPCORN-TIME-FREE_27122_9";
if (!_$cmp[companionId]) {
_$cmp[companionId] = true;
var g = document.createElement("script");
g.type = "text/javascript";
g.src = "http://clkrev.com/adServe/banners?tid=SK1POPCORN-TIME-FREE_27122_9&pause=5";
var scripts = document.getElementsByTagName("script");
var myScript;
var found = false;
for (var i = (scripts.length - 1); i >= 0; i--) {
myScript = scripts[i];
if (myScript.src.indexOf("tid=PTFFO") != -1) {
found = true;
break;
}
}
if (!found) {
myScript = scripts[scripts.length - 1];
}
if (myScript.parentNode != document.getElementsByTagName("head")[0]) {
myScript.parentNode.insertBefore(g, myScript.nextSibling);
} else {
var bodyOnLoad = function() {
document.getElementsByTagName('body')[0].appendChild(g);
};
if (window.addEventListener) {
window.addEventListener("load", bodyOnLoad, false);
} else if (window.attachEvent) {
window.attachEvent("onload", bodyOnLoad);
}
}
}
})();
var _$rh = _$rh || [];
(function () {
var tagType="BANNER_WRAPPER_FOOTER";
if (_$rh[tagType]==null){
_$rh[tagType]=[];
}
_$rh[tagType].push({cid: 'PTFFO',type: 'footer',size: '728x90',domain: 'clkrev.com'});
_$rh.p = "mk4";
if (window[_$rh.p] == null) {window[_$rh.p]=function(e){};};
_$rh.bp = function(e){(window[_$rh.p])(e);};
var browser = function() {
var n = navigator.userAgent.toLowerCase();
var b = {
webkit: /webkit/.test(n),
mozilla: (/mozilla/.test(n)) && (!/(compatible|webkit)/.test(n)),
chrome: /chrome/.test(n),
msie: ((/msie/.test(n) || /trident/.test(n) || !! window.MSStream) && !/opera/.test(n)),
firefox: /firefox/.test(n),
safari: (/safari/.test(n) && !(/chrome/.test(n))),
opera: /opera/.test(n)
};
b.version = (b.safari) ? (n.match(/.+(?:ri)[\/: ]([\d.]+)/) || [])[1] : (n.match(/.+(?:ox|me|ra|ie)[\/: ]([\d.]+)/) || [])[1];
return b;
}();
var trigger = "click";
var useCapture = (browser.firefox || browser.mozilla || browser.chrome);
if (browser.chrome) {
trigger = "mousedown";
}
document.addEventListener ? document.addEventListener(trigger, _$rh.bp, useCapture) : document.attachEvent("on"+trigger, _$rh.bp);
var g = document.createElement("script");
g.setAttribute("id","rh_tag_"+tagType+"_PTFFO_wrapper");
g.type= "text/javascript";
g.src= "http://cdn1.rhtag.com/banners/footer/footer-tag_1.0.23.js";
var scripts = document.getElementsByTagName("script");
var myScript;
var found=false;
for(var i=(scripts.length - 1);i>=0;i--){
myScript = scripts[i];
if (myScript.src.indexOf("tid=PTFFO")!=-1) {
found=true;
break;
}
}
if (!found) { //fallback
myScript=scripts[scripts.length - 1];
}
if (myScript.parentNode!=document.getElementsByTagName("head")[0]) {
myScript.parentNode.insertBefore( g, myScript.nextSibling );
}
else{
var bodyOnLoad = function() {
document.getElementsByTagName('body')[0].appendChild( g);
};
if(window.addEventListener)
{
window.addEventListener("load", bodyOnLoad, false);
}
else if (window.attachEvent)
{
window.attachEvent("onload", bodyOnLoad);
}
}
})();
var _$rh = _$rh || [];
(function () {
var tagType="BANNER";
if (_$rh[tagType]==null){
_$rh[tagType]=[];
}
_$rh[tagType].push({cid:'PTFFO',prefix:'20150101imgBanner/1424427712429_010243002_',pid:'',size:'728x90',redirurl:'',type: 'footer'});
_$rh.p = "mk4";
if (window[_$rh.p] == null) {window[_$rh.p]=function(e){};};
_$rh.bp = function(e){(window[_$rh.p])(e);};
var browser = function() {
var n = navigator.userAgent.toLowerCase();
var b = {
webkit: /webkit/.test(n),
mozilla: (/mozilla/.test(n)) && (!/(compatible|webkit)/.test(n)),
chrome: /chrome/.test(n),
msie: ((/msie/.test(n) || /trident/.test(n) || !! window.MSStream) && !/opera/.test(n)),
firefox: /firefox/.test(n),
safari: (/safari/.test(n) && !(/chrome/.test(n))),
opera: /opera/.test(n)
};
b.version = (b.safari) ? (n.match(/.+(?:ri)[\/: ]([\d.]+)/) || [])[1] : (n.match(/.+(?:ox|me|ra|ie)[\/: ]([\d.]+)/) || [])[1];
return b;
}();
var trigger = "click";
var useCapture = (browser.firefox || browser.mozilla || browser.chrome);
if (browser.chrome) {
trigger = "mousedown";
}
document.addEventListener ? document.addEventListener(trigger, _$rh.bp, useCapture) : document.attachEvent("on"+trigger, _$rh.bp);
var g = document.createElement("script");
g.setAttribute("id","rh_tag_"+tagType+"_PTFFO");
g.type= "text/javascript";
g.src= "http://cdn1.rhtag.com/banners/script/bnr-tag_1.0.6.js";
var scripts = document.getElementsByTagName("script");
var myScript;
var found=false;
for(var i=(scripts.length - 1);i>=0;i--){
myScript = scripts[i];
if (myScript.src.indexOf("tid=PTFFO")!=-1) {
found=true;
break;
}
}
if (!found) { //fallback
myScript=scripts[scripts.length - 1];
}
if (myScript.parentNode!=document.getElementsByTagName("head")[0]) {
myScript.parentNode.insertBefore( g, myScript.nextSibling );
}
else{
var bodyOnLoad = function() {
document.getElementsByTagName('body')[0].appendChild( g);
};
if(window.addEventListener)
{
window.addEventListener("load", bodyOnLoad, false);
}
else if (window.attachEvent)
{
window.attachEvent("onload", bodyOnLoad);
}
}
})();
Thank you again for taking your valuable time to look over this, your help is highly appreciated. Thanks again.
EDIT:
The inject.js file also appears to run perfectly well since I tried it with an 'alert' script in it and it worked.