Yes, when it can't find the N900, it just waits for it to be plugged in and starts automatically when it is.

I just installed a fedora 13 32bits os on my laptop. Installed flasher file "maemo_flasher-3.5_2.5.2.2.tar.gz". The usual command:
flasher-3.5 -F <FIASCO image> -f -R
was not getting executed successfully because it could not find any n900, so I tried this command:
flasher-3.5 -c -h RX-51:2101 -F <FIASCO image> -S usb
It gave me the following output:

Using serial port usb
Suitable USB device not found, waiting.
USB device found found at bus 002, device address 020.
Waiting for ASIC id...
Got 69 bytes.
ASIC ID:
05 01 05 01 34 30 07 57 13 02 01 00 12 15 01 95
17 10 68 68 71 7b 0d 45 55 c8 02 1c ab a9 01 65
31 36 d6 14 15 01 87 3b 4d cd ca f5 44 4d 24 ec
b2 ac 95 53 88 41 4f ab cd 66 15 09 01 f7 48 8f
28 a0 27 e5 b3
Sending 2nd image (14720 bytes)... done.
Sending ping... timeout!
failed.
Sending ping... pong.
Sending secondary (109440 bytes)... usb_bulk_read: No such device
timeout!
failed with error 0x0001
Sending secondary (109440 bytes)... write: No such device
failed with error 0x0001
Sending secondary (109440 bytes)... write: No such device
failed with error 0x0001

What does it mean when it says "Sending 2nd image (14720 bytes)... done."? What can be the reason the sending failed after ping-pong message?

The problem is solved finally. It was just a battery issue. I got a fully charged battery from a friend's 5800, and after plugging it in and starting the device connected to the pc holding a "U" key, turned the device in the flashing mode with a lil usb icon on the top right, and the flashing went just like it always has done for me. There was nothing wrong with my laptop as was suggested. The device was perhaps telling me about the battery through the status light, but if it showed a lil icon showing battery depleted or something wud have been a lot helpful.