Per Amazon's Device and Feature Specifications:
Kindle Fire (1st Gen) is based on Android 2.3.3, API level 10
Per Amazon Maps API FAQs:
Q: On which Kindle Fire tablets is the Amazon Maps API supported?
A: All Kindle Fire tablets and emulators except Kindle Fire (1st Generation).
Q: Is Amazon Maps available on Kindle Fire (1st Generation)?
A: No, Kindle Fire (1st Generation) does not include the maps library runtime.