If I might try to clarify what the problems with the InstantRoot from the "neiland..." site may be:
1) no internet access - I always ensure that I use a Wi-Fi link connection for this, as I'm playing with an unsubscribed Orange PAYG SIM.
2) site down or under heavy load, causing timeouts.
3) the "application installation" seems to require a 2nd stage whereby it accesses the "home" site for a 2nd part - code, data, I don't know.
4) anything that causes a ZIP extraction error/exception means the original ZIP isn't correct. Download again, replace and retry.
HTTH
As a comment on my personal exploits with an Orange 1.5 branded Hero:
Environment: unlocked Orange HTC Hero, 8GB microSD card, Unsubscribed Orange PAYG SIM (i.e. no Mobile Internet, calls etc.), 3 personal Wi-Fi LAN routers (2 bridged, Buffalo Tech WZR-RS-G54 with 1 cable modem, 1 Huwei ? ADSL router/modem), all Internet connected, using 128-bit WEP or WPA-PSK encryption keys.
Down-flashed to Orange-specific build 2.73.61.5 from the HTC support site.
Instant-rooted as per script.
FlashRec 1.6.2 installed as per script.
Apps installed (Astro File Manager, Titanium Backup, etc.)
Did the Titanium Backup, hit the "Problems?" button, thing to get BusyBox installed.
Backups taken and copied off SDcard to laptop (N.B. this includes various reboot/power-on types).
VillainROM 5.5 flashed.
Seemed to be mostly OK, except I lost the access to the new, white background MarketPlace, for one thing (Oops!). Left it for a while as I'd other things to do.
Currently experimenting with VillainROM 12.0, but I'm not entirely happy with the changed response to the Unsubscribed SIM etc.