I would check for firewalls, ipblockers, or some weird AV issue, disable all that stuff and try again.
If that doesn't work, how is your network setup, do you have a router/modem combo or separate devices? If Separate make sure proper ports are forwarded on the router, if they are, bypass the router and go straight to the modem to see if the issue exists there.
If you have a modem/router combo, ugh I hate those things, they can manifest weird problems, although it is not definitively that causing the problem, I would recommend for sanities sake to get your own router and have your ISP put the modem in bridge mode.
If none of that works, if you can, install titanium client EQ on another computer, and test to see if it's osmething with your computer or not, if it works on another computer then it's something weird with yours, if not it's likely something with your modem/ISP causing the problem
*this is all assuming you have everything setup properly from the install, i.e. selected the right executable*