To anyone having the problem with the BGM load error for file "(6-mysterious caf%20caf%C3%A9).ogg" located in the directory "...\SillyEmployee1.2_Windows\www\audio\bgm". Rename the file to "(6-mysterious café).ogg" so it will load correctly. If your PC is setup not to show file extensions then ignore the ".ogg" part and just rename the file name.
This error seems to be related to text conversion for special characters, in this case the accented "e" for "cafe".