The trial version doesn't have limitations.
How are you trying to preview sound? If you're new to AE, you should start here: Getting started with After Effects
It covers things like previewing. (Which is not with the spacebar, if that's what you were doing...)
What sort of error messages do you get when trying to import the PSD file? How are you trying to import it? Is it an RGB file or CMYK?
The problem I solved the sound by clicking on the Ram Preview. "I ate the fly"! Eheh!
Thank you for your strength!
The PSD image is RGB, 8 bits. Import / File.
In AE, comes the message:
"Error: could not open because xicara.psd is not a valid Photoshop document. "
But I do well in Premiere.
Are you saying that the PSD file imports into Premiere without any problems?
What version of Photoshop do you have?
What version of Premiere do you have?
What version of After Effects do you have?
And, when I ask what version, I mean the version number down to the last decimal. So, After Effects should be 13.0.2 or something like that.
Photoshop CS6 Version 13.0x64
Premiere Pro CS6 Version 6.0.0
After Effects CS6 Version 184.108.40.2068 (trial).
They all need to be updated. There were 4 bug fix updates to After Effects since the 11.0.0 version was released. If you're going to use CS6, your After Effects should be on 11.0.4
Although, why are you using the trial of CS6? There have been two other versions since then. The latest version is CC 2014 which is After Effects version number 13.