InfoPath Dev

 Do you need to copy the data to your main data source and be able to submit and save it, or do you just want to be able to display the data on your form. If it's the latter, then all you need is a repeating table with some filtering.  If it's the former, then the matter is a bit trickier.

 It may very well be an issue with the signatures, but most of the times I've encountered this error, it has been due to trying to assign a value to a node with an xsi:nil attribute (this attribute has to be removed before assigning a value to a node.  Do you have any OnUpgrade or OnLoad code that might be doing this?

 You'll need to make sure that you're adding the values to a repeating node, and read up on the XPathNavigator to learn about how to create and add new XML nodes using it. The AppendChild() and AppendChildElement() methods are useful for doing this.

 As Patrick pointed out, the .js file is a resource, to be referenced and used by the TaskPane.htm file.  As such, it is different from JScript you would use as "code behind" for a form and you won't see it if you open MSE.

 Please try using this expression instead (it has an extra "../") count(../../preceding-sibling::*) = 0

 Isn't that just the datetime with the hyphens and colons removed, and the T replaced with a hyphen?  You should be able to construct this with XPath's substring() functions.  No code needed.

 In the properties for the a dropdown, click the button in the entries: row, then the Filter data... button, Add.., change the first dropdown to "The expression" and then use the expression: count(../preceding-sibling::*) = 0This should cause it to only use the column values from the first row of data in the matrix. It should ...

 Another option would be to create a view that joins your database table with the DBXL Document table on the DocId key value and query that.  Doing so would be in keeping with the 2nf principle.

Form load events should run for new forms and when reopening existing forms, so what you describe is not expected behavior.  What is your form load event supposed to be doing?   Could you explain that with some detail? You can't create a hyperlink in code in InfoPath.  What you can do is create a hyperlink in your form, ...