I need with my website, i keep getting codes on my pages

Hello everyone im not a pro on web designing but i do know what im doing.
But i don't kno if it just me or its the website.
But on some pages everything works good.
IN some pages in the product pages. theres a link and mouse icon. and they could click the link where it says "click here for more details" everytime they click it. It takes them to a page where whole bunch of codes comes out. And in some pages it doesnt do it. and i have the same settings for all of them, i dont know what im doing wrong or what.
but heres the example in what i mean.

GOOD(how it soppose to be, click on the mouse icon)
http://sportstruckcapital.com/air%20lines.htm

BAD ( and this what it does to some pages, click on viair and click in one of the products)
http://sportstruckcapital.com/air%20compressors.htm

anybody who had this problem before and fix it, or anybody who know about this problem, please help me.

I update the software still the same problem. anybody know my problem ?

None of the links and files they go to have an extension, like .htm or .html so the server doesn't know it's an html file and just sends the text. If you add extensions to the files and update the links, they should work.

Hey thanks pal for replying. I'm going to try that. thanks alot