itunes sync error 54

Since getting a new pc and putting itunes on it and making a new music library. I have not been able to put my music onto my ipod touch 4th gen. Because its so old I thought the problem was the ipod so I brought a new ipod touch but I'm still having the same problem with it. I get this error message ipod touch can not be synced an unknown error has occured (-54). It seems to be putting the music on but the error message keeps coming up I click ok and it keeps going but after about it showing up 20+ times it then says to many files oppen and it stops syncing and all the music is greyed out on ipod. Is anyone having this problem or nows how to fix it.