Description of problem:
It's thrown a 500 ISE on the first step when one press "Next" after selecting the RHN Proxy version to be installed for the system.

Version-Release number of selected component (if applicable):
Satellite-5.4.0-RHEL5-re20100903.1-x86_64.iso

How reproducible:
from 1st attempt - on installing i386 RHN Proxy 5.3 (on virt. system)

Steps to Reproduce:
1. register a system (virtual i386 RHEL5 system for my case)
2. Have prepared the redhat-rhn-proxy-5.3-server-i386-5 channel synced there (the tools channels as well)
3. apply the tools channel for that system and install rhncfg* packages
4. run "rhn-actions-control --enable-all" on that system
5. Entitle the system with "Provisioning"
6. Refer to the UI "Proxy" tab from the "System" menu for that system
7. Start the installation process (press "Activate Proxy" button)
8. ISE...
  
Actual results:
500 - Internal Server Error

Expected results:
No ISE - process should go on...

Additional info:
---
The following exception occurred while executing this request:
 GET /network/systems/details/proxy/index.pxt?sid=1000010122&version=5.3 HTTP/1.1 (from browser)
 /network/systems/details/proxy/index.pxt (from Apache)

Date:
  Tue Sep  7 16:11:26 2010

Headers:
  Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
  Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
  Accept-Encoding: gzip,deflate,sdch
  Accept-Language: en-US,en;q=0.8
  Cache-Control: max-age=0
  Connection: keep-alive
  Cookie: rh_omni_tc=70160000000H4AjAAK; s_vi=[CS]v1|260B9EE6051D0D09-4000010BA00073DB[CE]; s_nr=1282119938342; s_vnum=1284709086467%26vn%3D14; pxt-session-cookie=30x7f7b3596b84ef95524be1a203f18e2ec
  Host: smqe-sat02.lab.eng.brq.redhat.com
  Referer: https://smqe-sat02.lab.eng.brq.redhat.com/network/systems/details/proxy.pxt?sid=1000010122
  User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US) AppleWebKit/534.3 (KHTML, like Gecko) Chrome/6.0.472.53 Safari/534.3

Form variables:
  sid => 1000010122
  version => 5.3

User Information:
  User admin (id 1, org_id 1)

Error notes:
  (none)

Initial Request:
  Yes

Error message:
  RHN::Exception: Invalid function: set_steps
  RHN::AppInstall::Process /usr/lib/perl5/vendor_perl/5.8.8/RHN/AppInstall/Process.pm 44 RHN::Exception::throw
  RHN::AppInstall::Parser /usr/lib/perl5/vendor_perl/5.8.8/RHN/AppInstall/Parser.pm 176 RHN::AppInstall::Process::new
  RHN::AppInstall::Parser /usr/lib/perl5/vendor_perl/5.8.8/RHN/AppInstall/Parser.pm 85 RHN::AppInstall::Parser::parse_install_section
  RHN::AppInstall::Parser /usr/lib/perl5/vendor_perl/5.8.8/RHN/AppInstall/Parser.pm 57 RHN::AppInstall::Parser::parse_tree
  Sniglets::AppInstall /usr/lib/perl5/vendor_perl/5.8.8/Sniglets/AppInstall.pm 450 RHN::AppInstall::Parser::parse_file
  Sniglets::AppInstall /usr/lib/perl5/vendor_perl/5.8.8/Sniglets/AppInstall.pm 61 Sniglets::AppInstall::load_appinstall_instance
  PXT::Parser /usr/lib/perl5/vendor_perl/5.8.8/PXT/Parser.pm 160 Sniglets::AppInstall::appinstall_start
  PXT::Parser /usr/lib/perl5/vendor_perl/5.8.8/PXT/Parser.pm 72 PXT::Parser::expand_tag
  PXT::ApacheHandler /usr/lib/perl5/vendor_perl/5.8.8/PXT/ApacheHandler.pm 522 PXT::Parser::expand_tags
  PXT::ApacheHandler /usr/lib/perl5/vendor_perl/5.8.8/PXT/ApacheHandler.pm 117 PXT::ApacheHandler::pxt_parse_data
  PXT::ApacheHandler /usr/lib/perl5/vendor_perl/5.8.8/PXT/ApacheHandler.pm 117 (eval)
  main -e 0 PXT::ApacheHandler::handler
  main -e 0 (eval)
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