When a node is linked to a file whose name contains spaces, the link doesn't work if any of those spaces is longer than one character.
In fact, Freemind is looking for a filename with all single space, no matter the initial name.
The attached zip file contains a test map with two target files ; one with double spaces in name.
One of the link points to that one but the single space filename is opened.
This is observed under XP SP2, JRE2 Standard edition 1.4.2_10 and freemind 0.8.1.
PS: Your freemind is just great, I use it daily for years. Many thank's !