This function takes a URL for a dataset database file and attempts to parse this into a TsmDatabase structure. The parsing routine will check for the following errors in the database file, causing a NULL return pointer:

• </tag> before a <tag>
• nesting of <tag> blocks
• <tag> without a </tag>
• <instance> can only occur inside <dataset>
• check that <tag> contains all required fields when </tag> found
• keyword/value pairs only valid inside appropriate <tag> group
• min/max-resolution values without a unit string
• check that min-resolution <= max_resolution
• invalid type value
• unparsable URLs for location fields