Javascript "unspecified error" in Open Layers

Answer 1

I have found the solution.

The problem was that I was creating the map when the DOM was ready with Jquery:

$(document).ready(function(){  ... //create map here [WRONG]

All you have to do is to create the map after the onload event:

window.onload = function() { ... // create map here [CORRECT]

Answer 2

The problem with Internet Explorer is that when the page hits the document ready or the window onload, that M$ browser cannot determine the dimensions of the map canvas yet. If you want to work around this, you might also consider setting your map div dimensions:

<div id="map" style="width:250px;height:250px"></div>