most likely its your internet connection.(99% chance i reckon)..i get an error every now and again too. more so using a dialup modem, if thats what your using.
modern hard drives are very reliable in that respect, if u still doubt the drive/motherboard/controller, try running some diagnostic programs or check the drive's SMART condition... programs can be found at the manufacturers webpage.
also... a little more info would be helpful. type of drive & modem, maker, mobo operating system etc etc etc
"Don't be too proud of this technological terror you have created"~Darth Vader, Star wars