Were you able to successfully deploy ProSphere 1.7 in your lab after correcting the underscores in the hostnames?
It was actually the ProSphere 1.7 Deployment Guide that had the information you needed,
Avoid underscores in hostnames
The Internet standards for protocols mandate that hostname labels can contain only the ASCII letters “a” through “z” (in a non-case-sensitive manner), the digits “0” through “9”, and the hyphen (“-”). No other symbols, punctuation characters, or white spaces are permitted.
If ProSphere encounters a host name with an underscore, users can be prevented from logging in.
You can confirm the situation by searching the log files for the following string:
IllegalArgumentException: Host cannot be null
