Since the last weekend of the SWTOR beta through headstart and launch, some people have had an issue with Error Code: 1003 and so far Bioware has been unable to figure out how to fix the issue. After much thought on the subject and some debate among some guild members we found a solution that worked for me and have at least formed an idea about what is causing the issue and so I'll go through and explain what myself and others have done in hopes that I can help with your problem.

Essentially I think that Bioware cannot solve the issue because there are so many variables to the problem but at its most basic there is something that is stopping the user from logging into the servers.  The error itself is characterised by either a blank server list after launch or a populated server list that when clicked will give you the dreaded Error Code: 1003 instead of bringing you into the character select screen.  The error seems to effect mostly Windows 7 X64 users but due to the nature of the error other OS's can be affected.  It wasn't until I installed SWTOR to my laptop which ran perfectly did I start thinking that the issue was either related to the OS or some other application was running interference. Before we delve deeper into the issue lets take a look at some quick fixes that have helped some users:

1. Run the application as administrator
2. Try running in Win XP Service Pack 3 compatibility mode
3. Try running in Win Vista compatibility mode
4. Disable Peer Blocker if you have it
5. If you have a modem/router combo with an extra router, make sure the modem is in bridge mode
6. Make sure your anti-virus / firewall settings aren't blocking the application
7. Flush your DNS

If these things don't fix your issue (and compatibility mode isn't a real fix in my opinion, just a band-aid solution), then you may have to get a little more specific.

Here's what I did... I took a look at my list of installed programs, specifically ones that launched at start up that accessed the network.  I uninstalled all download managers that I wasn't using, toolbars that were installed but disabled or hidden and really any other program that wasn't being used.  I had some ATI Catalyst USB drivers that didn't seem to impact my USB settings so I uninstalled those too.  Finally at the bottom of the list was a program called WinPCAP; it was installed previously to help with another network issue I had at the time, but my home network has been improved since so I uninstalled that.  I rebooted, launched the game, walked away to check sports highlights and when I came back to my office my game was inside the character select screen.  I logged out, took the application off compatibility mode, tried again and was able to login just fine. 

Hopefully this info makes it to you if you're experiencing this error, and I hope that it  can help some of you.  Happy hunting!