Javascript error from Winamp

Winamp is a commonly used MP3 player.

I usually like when an application does what the user is expected from it, that is why this javascript popup was strange for me, from a music player. Unfortunately the screenshot is in Hungarian, but it has the same error popup window as the Internet Explorer.

Translation:

A Runtime Error has occurred.
Do you wish to Debug?

Line: 460
Error: Invalid property value.

Yes No