iTunes library file cannot be saved. An unknown error occured (-50)

I'm a PC user and have iTunes 7.3, i've been trouble shooting for a while and nothing has worked so far. i am unable to add songs or movies, my computer is running on

Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 2
BIOS: Phoenix - AwardBIOS v6.00PG
Processor: AMD Athlon 64 X2 Dual Core Processor 4600+,MMX,3DNow ~2.4GHz
Memory: 2046MB RAM
DirectX Version: DirectX 9.0c
Card name: NVIDIA GeForce 8800 GTS
SoundMAX HD Audio

I have full administrative abbilities
alot of solutions for "iTunes library cannot be saved. An unknown error occured (-50)" are for macs and i need help for my PC, please help

 

Fixed

just did a system restore, forgot that i had it, i have kept my 7.3 and all my songs by using a system restore, windows xp has it under
start menu - all programs - Accessories - system tools - system restore
just choose a checkpoint from before the problem, PC users will get kept in the dark because it is a Mac program but if you do this it doesn't "fix" the problem but will put all the settings back to where they should be and iTunes will work as it used to. for those whom it is happening at the very begining i cant help sorry.