What're you using to change the map? IGSO?
As an alternative for now, right-click your dedicated.bat file.
Select edit, and you should see something like this:
start blockland.exe -dedicated -map bedroom
Change the text in red to the name of the map. Spaces can be included.
For example, if you wanted the map "Slate," you'd change it to this:
start blockland.exe -dedicated -map slate