External javascript file not loaded successfully on localhost

Hi experts , I am using external javascript files such as below:

<script type="text/javascript" src="lib/ext-base.js"></script>
<script type="text/javascript" src="lib/ext-all-debug.js"></script>
<script type="text/javascript" src="lib/ext-all.js"></script>
<script type="text/javascript" src="lib/register.js"></script>

but for third file not loaded successfully !! but others loaded successfully

however if I used same code and launch it from remote server , it is working very great. But I want to use locally for developing

why is sometimes loaded partially and sometimes not at all only locally . I have tried to clear cache but no advantage


thanks guys please help me

I have tried in chrome and explorer 8 , both of them not working locally but working only from remote server

What does the code do? External Javascript activity is highly restricted on local machines, especially with those two browsers.