OCIEnvCreate returns -1 what means it failed. As I see the function is related with the connnection establishing and fails most often because of:
1) lack of priviledges on some OCI shared libaries
2) Lack of PATH to the shared libraries (check LD_LIBRARY_PATH and PATH)
3) Messed up tnsnames.ora

I hope that's a hint. Just google and search metalink and otn for OCIEnvCreate problems