error message when trying to install MS office 2010 ProPlus

I downloaded the program being offered by my university, and when I start the setup, it unzips itself, shows progress, then an error message pops up:

Script:
C:\Users\Eun\AppData\Local\Temp\WZSE0.TMP\Office2010Proplus.vbe
code:
800A0400
expected statement

I tried locating the temp file, deleting it and installing again, but doesn't work either.
I have MS office 2007 installed, and have been trying the trial version of 2010 before I realized my school offers it to students. lol. Perhaps that messed up the system?
Help would be really appreciated! (I'm no techie, so step-by-step instructions would be really nice)