I don't have redhat 5.3, nor x64, but it's likely you'll have to perform the following to install:
# yum search expect
expect.i386 : A program-script interaction and testing utility
# yum install expect
Installing: expect i386 5.43.0-5.1 base 158 k
Is this ok [y/N]: n
That should give you the required dependency to install the agent. Installing an expect tarball is not suitable because the agent installation is checking the rpm database, which will not have the details of your source compile.