ChemSpider Web API, anyone?

I'm trying to do a structure search using the published ChemSpider Web API:  http://www.chemspider.com/WebAPI.aspx

I thought it would be sufficient to get the form they provide, put a molfile into the designated area, add an submit button and it works.

But all I get back are blank pages with no content. No error messages, nothing useful.

How is the darn thing meant to be used?

UPDATE: Adding a method="post" to the form did the trick, but apparently only substructure searches with unlimited result set are supported. This results in very poor performance with structures of low selectivity. Still not good

UPDATE 2:

1. I had an extra line in my molfile.
2. There is really a bug in the API. Substructure search triggers exact search and vice versa. Since the API is heavily in use with workarounds to this bug, fixing this would break many applications.