Try this from Apple. It is the same for error 50 but could work for 1439 as well:"
Disconnect the iPod from the computer and close iTunes.
Highlight all of the following 10 lines of text that begin with regsvr32 and then choose Copy from the Edit menu of your web browser:
regsvr32 /s softpub.dll
regsvr32 /s wintrust.dll
regsvr32 /s dssenh.dll
regsvr32 /s rsaenh.dll
regsvr32 /s gpkcsp.dll
regsvr32 /s sccbase.dll
regsvr32 /s slbcsp.dll
regsvr32 /s mssip32.dll
regsvr32 /s cryptdlg.dll
regsvr32 /s initpki.dll
Open the Notepad program by navigating to:
Start > All Programs > Accessories > Notepad
In Notepad, choose Paste from the Edit menu. Note: Make sure that the text that appears in Notepad is the same as what is shown above.
From the File menu, choose Save As.
For File name, type appleipod.bat and save the file to the Desktop.
Close Notepad and locate the appleipod.bat file. It should appear on the Desktop
Double-click the file and you will see a black window appear on the screen for about a minute. Wait until the window automatically disappears and proceed to the next step.
The appleipod.bat file can be deleted at this time.
Open iTunes and connect the iPod.
When the iPod appears in iTunes, restore the iPod and resync your content.
Note: Because some malware may unregister the .dll files, make sure you have the most recent updates to your anti-virus software and then do a full scan of your files.
If the above does not work and you get the "It says that I have 148 GB (out of 160) available, but the pie charts say that I have 0 Bytes used and 0 Bytes free" sounds like you have either a bad hard drive or a bad hard drive cable. I would check the hard drive with a Zif-to USB connector.