APEX

I have Oracle Database 10g Express Edition Release 10.2.0.1.0 installed on windows XP. I want to develop an application using oracle express (apex), so I thought it would be a good idea to upgrade apex (from the default apex 2.0 that came with 10g xe) to the latest, release 3.1, before starting. I have tried up to upgrade twice & it has failed. The first time was my fault since I aborted the apexins.sql because I ran it from the wrong directory & it couldn't find the files needed. When I re-ran, I got errors (of course). The log file showed:
...create flows user
create user FLOWS_030100 identified by "853AG8UTTMWMHDOY3N0CEM2CPU49WZ"
ORA-01920: user name 'FLOWS_030100' conflicts with another user or role name
alter user FLOWS_030100 default tablespace apexadmin
ORA-00959: tablespace 'APEXADMIN' does not exist
alter user FLOWS_030100 temporary tablespace apex
ORA-00959: tablespace 'APEX' does not exist
... <then towards end of log file, it had the following error>
Performing Application Express component validation - please wait...
Completing registration process.
Validating installation.
FAILED CHECK FOR PACKAGE BODY WWV_FLOW_JOB

I followed troubleshooting instructions, unistalled 3.0, deleted synonyms & tried again, with statement:
@apexins apexadmin sysaux sysaux temp /i/ . This time the log showed:
...create flows user
User created.
alter user FLOWS_030100 default tablespace apexadmin
ORA-00959: tablespace 'APEXADMIN' does not exist
alter user FLOWS_030100 temporary tablespace sysaux
ORA-10615: Invalid tablespace type for temporary tablespace

I did not see any other errors (like the failed package body), but in both upgrade attempts, it looks like it expects the 1st param for apexins script to be the default tablespace instead of the password. Any ideas?
So here's my questions:
1) Am I following the correct installation instructions for apex rel 3? From what I read, I believe I can go directly from apex rel 2.0 to 3.1. I noticed that there were 2 different install docs & they were different. Both docs said to run the change passwd script(apxchpwd) after installation, but one installation doc had 2 additional scripts (which I didn't run). Can someone please point me to the right install instructions?
2) Do I need to install HTTP first??? If so, where do I get it for oracle XE? I see instructions for HTTP but I thought HTTP was already INCLUDED in oracle 10g express by default according to the install doc which says"
"Oracle HTTP Server uses the mod_plsql plug-in to communicate with the Oracle Application Express engine within the Oracle database. The following products include appropriate versions of HTTP Server and mod_plsql:
• Oracle9i release 2 (9.2) or later
• Oracle9i Application Server release 1 (1.0.2.2) or later
• Oracle Database 10g Companion CD release 1 or 2"
I assumed oracle 10g XE is > oracle 9.
• Oracle Database 11g release 1
I assumed that I didn't need to install HTTP since oracle xe is rel 10. I guess that's an incorrect assumption.
3) It says that 85M is required in SYSTEM tablespace for apex 3. The system tablespace size is 76800 (default).
Should I increase it before attempting to upgrade again? (I expected the default to be big enough since apex comes with the db)
4)Any suggestions/tips for starting over are more than welcome! Again I saw > 1 doc on how to cleanup a bad installation. Both said to drop the flows_0300 user, but one said to exec wwv_flow_upgrade.switch_schemas, which I did before I did attempted the 2nd install. Also, Is there any other software that needs be to installed before or after apex 3.1? Anything else I missed? The documentation is inconsistent & not accurate!
Please help! I'm frustrated already!
Thanks.