After Effects not rendering layer transitions

Question

Dear Gurus,
This is my first day with After Effects but i've done plenty of research and hopefully my main query here isn't a silly one.
I have a composition (made from JPEG sequence) with a number of layers and finally managed to add a 'block dissolve' effect between them.
My Setup:
MBP 8GB RAM, After Effects CS4, OSX Lion (developer release).
My Questions
(1) When I preview the sequence everything looks great (albeit slow) and the block dissolves show up fine.  When I render it out, it also looks good except there is no block dissolve transitions - it just flicks from one layer to the other.   FYI - I don't have openGL enabled.  I am trying to render to quicktime format with H.264 encoding at 90% quality.
(2) In iMovie (sorry for the comparison), it was really easy to just drop a transition between two sets of footage.  In After effects, I added the effect to the clip then had to click the timeclock icon and specify the duration etc etc..  Not a big deal but is there a easier way?
(3) Also in iMovie there appeared to be a lot more normal/bland transitions effects like cross fades.  I'm sure they are possible in After Effects - could someone give me a quick pointer?
Thanks!

Answer 1

(2) In iMovie (sorry for the comparison), it was really easy to just drop a transition between two sets of footage.  In After effects, I added the effect to the clip then had to click the timeclock icon and specify the duration etc etc..  Not a big deal but is there a easier way?
That's how AE works. It's simply a different paradigm.
(3) Also in iMovie there appeared to be a lot more normal/bland transitions effects like cross fades.  I'm sure they are possible in After Effects - could someone give me a quick pointer?
Of course there is - you stack and combine effects to produce new effects and unique looks which for all intents and purposes can be consecutive applications of transitions as well - one linear wipe from the right, one from the left, one from top, one from bottom and all with different timing - animated organic crop. Once animated, you can save this as an animation preset and re-apply it to otehr layers. Check the help for the gory details. Of course you can also get tons of extra plug-ins to add more and more such stuff, but if I may be so bold: If your sole intention is to produce slideshows with canned transitions, then you are using the wrong tool and on some level mis-using AE. As I already said above - you need to get into it if you realyl want to exploit its creative potential. AE is not an editing tool or any such thing, it is a versatile compositing tool and that power comes with a price. Even if you ever only use 0.5% of it, you need to adapt your workflow.
As to why your effects don't render is an open question, but since you yourself mention that this is your first day with AE, chances are you have flipped some switch wrongly in teh render settings, aere using OpenGL or something silly like that. Perhaps you can provide screenshots or a detailed listing ofd your comp settings, timeleine and render settings to help unriddle this...
Mylenium