iTunes "Choose Library" my old library file is grayed out and unchoosable

So, the core of iTunes's being is in the "iTunes database file" type file, which is given the default name "iTunes Library" with no extension. Mine is 6 MB. You should be able to open iTunes using one particular library file by holding down Option when you click iTunes's icon, and then clicking "Choose Library", and then browsing to the file. The file should have black text and be clickable. My "iTunes Library" file is displayed in gray text and is not clickable. However, it is byte-for-byte identical to another copy of itself which is clickable. The filename is identical, they are in different directories with the same exact permissions.

Currently, when I do "Get info" on the functional "iTunes Library" file, it says General > Kind: iTunes database file. When I do "Get info" on the non-functional "iTunes Library" file, it says General > Kind: Document. How can I change "Document" into "iTunes database file"? It IS an iTunes database file. It is byte-for-byte identical to the working version, I compared them two ways.

I have solved my immediate problem, but not my longer-term problem:

I downloaded "Quick Change", and changed the type of the file to "hkdb" and the creator of the file to "hook". This made the file non-gray and allowed iTunes to open it, which it did successfully and happily. However:

I need to be able to do this from the command line, for what I am doing. Is there a command which changes "kind" and "creator" in Mac OS X 10.5? There must be, right? I can't find it with Googling, though.

I had this same problem again. The solution was different this time:

Change the iTunes Library's filename from:

my-library

To:

my-library.itl

Be sure to use the Terminal, otherwise OS X just "fakes" it and makes the new name display, without actually changing the filename extension:

prompt.$ mv my-library my-library.itl