Problem: Eudora could not be opened because of an error type 3.

Solution:

This means that you need to update CarbonLib, which is available in Runway. If it is not there then download the CarbonLib 1.6 from Apple's website http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English-North_American/Macintosh/System/Other_System/CarbonLib_1.6.smi.bin, then restart the computer and run Eudora. If the above link doesn't find the CarbonLib file, go to Apple's website http://www.apple.com, click on Support and in the Search Support field type in CarbonLib 1.6.