I can tell by checking the error you shared in both the question and your answer to Mark that something about your ODK installation seems wrong.
I want you to check if you can use Eclipse for ODK manually.
You can also check if the ODK versions seems right on the Configuration Parameters: Target 1500S Options screen. However, I expect that once you get access to Eclipse the problem will be solved.
I will be following the activities on this question to make sure the problem is solved.