If you are programmer, SAP ABAP/4 , perl, shell or Lotus, AS400 programming is more appropriate for you to adapt.
If you have a good IT support background, you can learn UNIX, Openview,
CA or iplanet server.
I don't think it is easy for a programmer to transfer to security. (You must have a very good background on Networking and system)
I mean, it is just my own opinion, not targeting on a particular person. You are too sensitive.