OLE DB error: OLE DB or ODBC error: Operation canceled; HY008.

Got this error after adding an attribute to a dimension.
Looking closely at the dimension and then straight in the SQL server found out that it had two values possible for no value:
'NULL' and '' (empty string).
Solution: making sure all the "unknown" were the same (I choose and empty string) fixed the issue and the dimension was processed successfully.
Update 22/11/2013
A different solution: wasn't a time out, it was the "warning" at the end of the dimension processing error message, and the details are below:

http://www.sqlservercentral.com/blogs/dknight/2009/03/02/cube-processing-error-hy008/

Where did all my values go to?

Or: Mess with values that you enter in a datasheet view.
This is the scenario:
There is a form which contains a sub form which is linked to values in a text box on the form (or to values in a different sub form). The form is displayed as datasheet.
You enter the values you need, all of them are from different linked tables,
and when you go the the next record your values had disappeared and instead you get totally different values!
For example:
the value should be "style" in the outside form
so for the style "myStyle" on the Parent Form the values in the sub form should be:

Bold 5%
Italic 10%
Normal 30%

But when you insert them they're seems to be taking from an existing style somewhere else. When you look in the table in the database, the values had entered correctly, it's just that the display is wrong.


The solution:
Add the id of the linked value to the subform, just hide it. That sort the mess out!

Environment:
Ms-Access 2003, Linked SQL tables.