Installation aborted when flashing rom...

I've been using this HTC Hero GSM for about one and a half years now, and I'am deciding to give it a new look before it is replaced by the next nexus expected to come later this year. I chose the CM7.2 stable and downloaded it to my sdcard. The was a step about installing a custom recovery image which I cannot do becasue this hero cannot be recognized by the computer when plugged in (therefore I usually depend on dropbox for file transfer). Then I shut off the device and powered it on holding the home key. It soon entered this recovery screen, and there were four choices to do(listed in the picture below).

Here comes the problem: no matter what rom I tried applying, it would abort soon after it started, and when I boot it up, it will go back to stock. This picture shows what happened.



I know its not clear at all, so this is what is written up there: the title(?), the options, and the log. In the backgroud, it says [menu] Enter and [home] Cancel

Android system recovery <2e>
Android system recovery utility

reboot system now
wipe data/factory reset
wipe cache partition

--Wiping data...
Formatting DATA:...
Formatting CACHE:...
Data wipe complete.
--Install from sdcard...
Installing update...
Installation aborted.

Anyone with ideas?