You can
download .NET version 1.1 directly from Microsoft and install it. This installs side-by-side with other versions of .NET (i.e. it does not replace other version you already have).
More Information
The current version of PlayerPal needs .NET 1.1. Unfortunately, the PlayerPal install program sends you to the wrong web page to download .NET 1.1! This problem is caused by the Microsoft installer. It is not a PlayerPal bug. However, this will be resolved in the next major release.