If it takes longer to download the map files, than the map is in play for, then you will not connect.
Find the website for the server and download the packs manually if it takes too long.
Not sure what you mean "updating to 436..." as GOTY is 436 final.
If you have updated from a lower version, you do not have the GOTY edition, or somehow downgraded it.
If you have no interest in using UEd, then the 451b update is safe for you to use.
If you intend to play modern UT99 mods and maps, you are going to need a faster PC.
If you only want to play the original maps, and maybe 1 or 2 mutators at a time, the old rig is fine.
My AMD3200 + 2GB RAM + ATI HD3600 512MB is not enough to play old UT with all new updates and huge textures, plus a handful of mutators.
Make sure you have installed the DirectX 9 runtime files, and you can use faster features of your newer GFX card.
Unless you actually have a DirectX 5-7 card, you need to move into this century with DX8 or 9 renderers.
The older cfos network driver may help, and is very useful for improving ping time
http://www.cfos.de/en/download/download.htm#speed_other
You can use this page to see you current network setup
http://www.speedguide.net/analyzer.php
And get their tweak tool
http://www.speedguide.net/downloads.php
Finally, and most importantly so you stop looking like a complete amateur
Your keyboard has a "Print Screen" button, just like everyone else
Press that button, then paste the screenshot into Paint or Irfanview or whatever you can save a jpeg with.