This was in the release notes for 1.5.2 which noted the things that will be fixed in 1.0.4 which includes things for Esplora:
ARDUINO 1.0.4 - Not yet released.
- Fixed malloc bug (Paul Stoffregen)
- Fixed memory leak when calling Ethernet.begin() multiple times.
- Fixed SD example listfiles.ino
- Fixed a lot of Esplora examples
- Sort entries in preferences.txt (Shigeru Kanemoto)
- Fixed some wrong translations
- Fixed NPE due to permissions IO error
- Updated drivers for Windows (all-in-one, signature for Win8)