\033bQ.\033n \033bError: R_TextureNumForName: SW1BLUE not found\033n
What does this mean ?
\033bA\033n. You have named the \033bshareware WAD\033n as doom.wad, it should be named as \033bdoom1.wad\033n. I'm using doom1.wad, which is 4196020 bytes. If yours is that size, call it doom1.wad, remove all the other wads, and off you go :-)

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\033bQ\033n. I have an \033bUltimate Doom WAD\033n, what should I name it ?
\033bA\033n. \033bdoomu.wad\033n in the Doom directory. This WAD contains four episodes, instead of the normal 3. Load in the DoomGATE.rexx file in the directory containing DoomGATE and change the Max_Episode value to 4. You can then access all 4 episodes. The 4th is called Thy Flesh Consumed. doomu.wad is 12408292 bytes long, although versions have been spotted that differ slighty from this size.

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\033bQ\033n. How many DOOM ports are there ?
\033bA\033n. 5, at last count. 6 Maybe. The main ones are ;
ADoom : Nothing Required
AmigaDoom : RTGMaster, AHI, ixemul.library
AmiDoom : Unsure
PsiDoom : AHI

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\033bQ\033n. Which do you recommend ?
\033bA\033n. At the minute, ADoom. Try them all though before you pick one :-)

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\033bQ\033n. I can't seem to download files from the web. Also, do I really need the source to play, and why doesn't Doom fill the screen ?
\033bA\033n. If you have trouble downloading files from the web using IBrowse or Voyager or anything, \033bmake sure\033n you are downloading them via the popup menu that appears when you press the right mouse button over the link. Select download to disk, or whatever. Or you can sometimes hold the shift button when you left click on the filename. I always use "wget" from aminet to download files like this. Just do "wget http://what.ever/thing.lzx". Wget needs Ixemul.library though, so you can't use it to download ixemul.library....
Oh, and you DON'T need the source to play it, as some people seem to think :-)
Doom is 320x200, so selecting a screen mode larger than this will just make it use a small area of the screen, so there is no point really :-)