You can import a project into another project---but that imports the whole thing. If you wanted to just import a couple of things then you could either import the whole project and delete what you don't want (which might be a pain) or you could reduce the other project to the compositions that you want and then import that reduced project.
Thank you for the response. Something weird was happening and I didn't realize it when I was getting the error message. When I had the AE comp open that I wanted to import the comp/project file into I was receiving a weird error. AE didn't recognize the project file I was trying to import. It had a long audio type of extension on it after the .aep. I simply opened the project file in question and did a "save as" and then I was able to successfully import it into the other project file like I had originally intended.
It was weird becasue I was scratching my head because I recall doing it alot in CS4. Anyway my issue is resolved and thank you for the link, great video.
AE also had a problem recognizing a standard WAV file exported from AU. I was able to import into PP fine and WIN MediaPlayer played it fine as well. AE was recognizing it as a PEK file. Very weird. I had to export the file from AU again and it imported it fine.
Attached is a screen cap of the error that was being thrown. In the top left of the import dialog box you can see my AE proj file I was trying to import. If you notice the name of my comp is "Video Assets" and AE was recognizing it as "Video Assets 1.aep blah blah.
AE 5.5 / MC 5.5
MS Windows Vista Home Premium 64-bit SP2
Intel Core 2 Quad Q6700 @ 2.66GHz 42 °C
Kentsfield 65nm Technology
8.0GB Dual-Channel DDR2 @ 332MHz (5-5-5-15)
ASUSTeK Computer INC. P5QL PRO (LGA775) 35 °C
HP w2408 (1920x1200@60Hz)
512MB GeForce 9400 GT (MSI) 43 °C
488GB Western Digital WDC ATA Device (SATA) 37 °C
WD Virtual CD 1110 USB Device
ATAPI iHAS120 6 ATA Device
Realtek High Definition Audio
It appears to be attempting to import Video Assets 1.aep 48000.cfa (which is a preview file generated by Premiere) rather than Video Assets.aep.