Hi leslielopez94,
Welcome to the Support Communities!
I would first suggest that you backup your iPod touch using iCloud before you troubleshoot on your new computer.
The article below may be able to help you with this issue.
Click on the link to see more details and screenshots.
Using iPhone, iPad, or iPod with multiple computers
http://support.apple.com/kb/HT1202
If you continue to get the (-50) error message after following the instructions above, then click on the link below for more information.
iTunes: Advanced iTunes Store troubleshooting
http://support.apple.com/kb/TS3297
These alerts occur due to timeouts or conflicts trying to write a file during download.
Cheers,
Judy