Apple TIL file #22141 confirms this and offers a solution: "Make sure you are using version 1.4.1 of the Apple FM Radio application and version 1.2 of the FM Radio Extension. These are the versions that are compatible with Mac OS 8. The Apple FM Radio application is normally stored in the Applications folder. If the Apple FM Radio application was moved prior to the installation of Mac OS 8.1, the installer probably did not delete the older version of the FM Radio application. You may still have an older version the Apple FM Radio application on your hard drive, which would cause the error message you described."
Aliases Cannot Find Originals (# 30350) Q. I updated my System Folder from Mac OS 8.0 to 8.1, backed up my entire hard drive, reformatted it as Mac OS Extended format, and restored all my files from backup. Now, none of my existing aliases work, and any new aliases I create cannot find the originals either. What's wrong? A. If you updated a Mac OS 8.0 System Folder which had the Text Encoding Converter disabled, the 8.1 update will install a new version of that extension, but it will still be disabled. Text Encoding Converter is required on HFS formatted startup disks. Drag the Text Encoding Converter extension from the Extensions (disabled) folder to the Extensions folder and restart. Your existing aliases should now work, and you can create new aliases.
Using non-Apple CD-ROM Drives (#30346) Power Computing customers and Mac OS-Compatible computer customers may need to create special Disk Tool disks for using with Mac OS 8.1. This process will be the same as previously with Mac OS 8.0.