[help] PHP/Visual basic online auth system

[xvisceral]

Okay, so I am using this code to verify that people have authorization to use my program.

It checks an online database... Here is the code

-see attachment below for full php/vb code-

The code works fine for almost everybody...but for some users, it will randomly not connect to the website at all. Has occured on XP, Vista and 7, but is also confirmed working on XP, Vista, 7.

Does anybody see a reason that it could be?

For example: the user Bob with the ID of 123 is in the database, but when Bob on his computer with ID 123 runs it, it does not access the website, so it says that he is not allowed permission to the program.

Bill with the ID 456 enters Bill and it connects fine. both users are in my database