Are you flashing them from recovery or trying to unzip the folder?

*EDIT* Make sure you are downloading complete ROMs.

 

Turn the phone off
turn it back on while holding volume up
wipe data and dalvik
then go to flash zip from sd card

p.s. check your md5 sums to make sure you didn't get a bad download

 

How exactly are you getting the ROMs onto your phone's SD card?

Are you transferring them from a PC, or downloading them directly on the phone?

Are you taking any measures to check the integrity of the download before you try installing them?

Are the ROM file names listed when you choose the menu item "Flash zip from sdcard", do you see the ROM file name listed as you expect on the SD card?

Are their any other error messages which precede the "can't open" message?

What ROMs did you try?

eu1


PS In the meantime, if you want your phone back while you work on this, you can do a "Nand restore" from the recovery menu to get back your non-rooted OS (assuming you followed the instructions and performed a Nandroid backup). Just remember to wipe before installing the new ROM (unless you are just doing the "engtools" overlay thing).

 

There is no "best" because it is impossible to account for the tastes of different users.

But... didn't you just say you installed a ROM? Are you already looking for another one?

I will say that some neophytes start off with ROMs that are development ROMs - that is, full of bugs. Then, they bounce around trying ROMs that other folks with more experience describe as "cool", and find that they also have this bug, or lack that feature (one they want to have), and in the end conclude that "hey, all root ROMs suck".

A way to avoid that is by starting with a ROM which is as close to HTC stock as possible, but with a few goodies tossed in - overclocking, SU, and perhaps wireless tethering. That will give you a familiar experience with very few bugs and added capabilities and speed. You will always have it "in your pocket" with a good Nandroid backup, and can return to it if you are having troubles with a more experimental ROM you are trying out.

Think of it like mountain climbing - you don't try for the summit immediately, and you always have a base camp to retreat to when the weather turns nasty. (Over time, the base camp goes higher up the mountain as you gain time at altitude.)

That's why I suggested T2noobs Plain Jane update - I haven't tried it, so I can't vouch for it, but it should be pretty straightforward, and it is based on the July 2010 OTA. The other alternative is to simply use your existing ROM with the "engtools" flashed over the top of it - that doesn't even require re-configuring a "factory reset" ROM.

eu1