Updating fonts, MOVEFILE_DELAY_UNTIL

I wish to update some fonts on my user systems,
but am having problems with some fonts (not all).

These work:
arial.ttf
arialbd.ttf
arialbi.ttf
ariali.ttf
verdana.ttf
verdanab.ttf
verdanai.ttf
verdanaz.ttf

These don't work:
tahoma.ttf
tahomabd.ttf

With these last two font files I have problems,
others get updated, but the last two don't.

This is the sample code used to move all fonts from my folder to windows font folder:

Code:

MoveFileEx("c:\\myfolder\\tahoma.ttf", "c:\\windows\\fonts\\tahoma.ttf", MOVEFILE_REPLACE_EXISTING | MOVEFILE_DELAY_UNTIL_REBOOT);

All succeeds but the last two... have no idea why.
Is it possible that the tahoma.ttf is already in use by windows at reboot?

All fonts from my folder are deleted, including tahoma files.
Tahoma files in fonts folder don't have a READ-ONLY or similar attribute set.

Is there a easier way to update fonts?

Note: I'm aware of this but haven't done anything about it yet...
other fonts are updated, so...

Testing on win xp sp3.

Updating fonts, MOVEFILE_DELAY_UNTIL_REBOOT problem