We were just doing a remote ArcIMS install for a client and ran into something that I have not seen before. This was probably the 300th install (seriously) that I had done and this was the first instance of this issue that I have ever seen.
What was happening was this: Fresh install (CFMX using JRUN on Win 2003), diagnostics all OK. Then when we tried to start the administrator, the usual first time prompt for user name and desired password appears, which is all normal. After inputing that information, the admin would just hang. Nada.
So, it seems for some very bizarre reason, ArcIMS was not able to create the initial AimsAdmPw file in %install dir%\AppServer. So, after copying an existing AimsAdmPw file over to the new installation, everything worked as expected. Only rub: you'll need an existing file for this solution to work.