Internet Computer Sharing on Macbook

Hi guys,
I have been googling over 2 hours and still can't get this solved and really need help with this.
I live in a place (university building) where the usage of routers is not allowed. Each room has a ethernet (LAN) cable in a room, and you can use internet by logging into the network through a web browser + having a univ. proxy set up.

Now uptil now, I was able to use in my room ICS on my Macbook Pro (OS 10.6.8). Everything worked prefectly - I used it connect my iphone and ipad to my comp - this allowed me to update stuff on ipad+iphone that I use daily.
.
Now something seems to have changed and I cannot set up an ICS anymore.


1. Is it possible that ISP can block even ICS from my Macbook to my gadgets at home? If so, is there a way how to get around this at all?

2. I have played around with the settings and now I don't even manage to get the upwards facing arrow set up that indicates that my airport starting sharing (I might turn on internet sharing by my gadgets can't connect to it).
Last night, before I played around with the settings, I got the "set-up" right but even after my ipad connected to my Macbook and all seemed fine, it didn't download any data.

Any help will be much appreciated.

 

Tampasteve, thanks for the answer.
Unfortunately I cannot do so. The only internet access that I have is here on the campus and in my house where I live - which is also a university building.
I can tell you that just a week ago or so it worked - and it worked for 2 months.
But in prior semester, it didn't. My sense is that it's connected to the univ. IT administration - but then that would mean that the answer to my first question is YES.