I am having this problem as well, on two different Windows 7 Enterprise SP-1 32-bit computers, with all important updates applied as of 4/17/2015. I can install the fonts (either by opening them and clicking install, or by dragging them into the fonts folder).
They will install fine and be usable, but after some time (and could be after a reboot or even after being in hibernate mode, but I haven't determined that it's just those cases), the fonts will no longer be available.
The symptoms are that applications that use the fonts can't see them (happens both with MS Word, CorelDRAW), and the fonts in existing documents are substituted with other fonts. The font does not show up in fonts under Control Panel. I then have to reinstall
the fonts (at which time I get a warning for each font that the font is already installed and do I want to replace it). I replace the fonts and then the fonts are available again, albeit for some period of time before the above happens again.
All of the problematic fonts appear to be OpenType fonts, although I don't know for sure that this doesn't happen with TrueType fonts.
While a workaround exists (reinstall the fonts almost every time I need to use them), it boggles my mind that this issue continues to happen for something as simple as fonts. Any other solutions I should consider?