Definitely go with 5.0
I'm not sure about the error you came across.
and Jade, are you saying that I should go with 5.0, instead of 5.1 ?
About the error, I just couldn't "fix" it.. doesn't anyone facing this b4 ?
Can you post more information about your error? What errors preceeded it? Can you inspect the error log (/var/lib/aolserver/service0/log/error.log by default) for more errors?