I had read carefully of all the posts, and decided that the problem in my n900 is its battery level too low so I was not able to flash the stock kernel. I need a desktop charger, fast.

I checked ebay and google shopping, all those stores that sell bl-5j desktop chargers are in hongkong, and I can not wait that long. It is my only phone and I desperately need it fixed.

So, want to buy BL-5J desktop charger (From US or North America)

You can also use a 5800XM and a Nokia N95 to charge the battery (you might also be able to use an E66, but not sure about that).
If you're wondering about size ignore it, the pins are identical.

Try plugging the phone in to the PC and leaving it to trickle charge for a few hours.
This has solved the problem before.