What do you mean by intro templates? If you mean title graphics, you might check out some of the tutorials over at VideoCopilot.net; they have a few tutorials that could involve titles.
As for your AEGP Plugin AAF" question...We will need a lot more info. Where do you see this? What are you doing when it happens? What's the full message? What are the specs of your computer? What version of AE are you using?
1) I'm using version CS3.
2) I want Intro Templets like : http://youtu.be/OLgiMmhHsf8
something this kind of templetes For only after effects cs3. Must check sir.
3) For AEGP Plugin AAF" :
a) I saw it while working on Adobe After effect CS3, when im importing Audio file in MP3 format,
b) Full massage is : after effects : AEGP Plugin AAF: Error occured while creating project (5027 ::12).
c)System specs : windows xp, Service pack 2, intel(R) Pentium 4, CPU 3.00GHZ, 512 RAM.
You need a new computer. I was running AE7 (the version before CS3) on a machine with a Pentium 4 with 1 GB of RAM and it wasn't exactly zipping along then (especially with HD). I mean, it worked, but you really need to upgrade; at least your RAM. I didn't know CS3 worked with less than 1GB of RAM.
Anyway, even with the current version of AE (CS5.5 AKA After Effects 10.5) it's not suggested to use compressed audio like MP3's. Convert the sound file to a WAV first.
As far as templates go, that template you linked was pretty awful and fairly basic. It makes use of a lot of stuff from VideoCopilot.net including the Sure Target plugin. Go through the basic training, then head over to VideoCopilot.net and you'll be making stuff like that pretty fast.