Check your ms_iostripstdoutbuffercontenttype() function, I think it's setting your $contenttype as text when it should be setting it as PNG. Also, Chrome is complaining that this link is 404'ing:

http://134.74.146.40/~Oviedo12/final/subway%20crowding/js/theme/default/style.css

edit: Also as Dave points out in the comment, set your map to a static path instead of a dynamic one and see if that helps.

Check your ms_iostripstdoutbuffercontenttype() function, I think it's setting your $contenttype as text when it should be setting it as PNG. Also, Chrome is complaining that this link is 404'ing:

http://134.74.146.40/~Oviedo12/final/subway%20crowding/js/theme/default/style.css

edit: Also as Dave points out in the comment, set your map to a static path instead of a dynamic one and see if that helps.

edit x2: Change your $oMap in your php code from this:

ms_newMapobj("../maps/dynamic.map");

to this:

ms_newMapobj("http://134.74.146.40/~Oviedo12/final/subway%20crowding/maps/dynamic.map");