Windows Vista Fonts

Hi,
When I try to upload into Windows/Fonts/ folder some text skins, i receive a
firewall message, what says to me: Continue or Cancel. If I press Continue,
happens nothing, if I press Cancel happens nothing, so, i can't install any
new fonts skins. .
When I look into Problems and Report Solutions, I see this:
Windows Explorer has stop working and:

Problem signature
Problem Event Name: APPCRASH
Application Name: Explorer.EXE
Application Version: 6.0.6000.16549
Application Timestamp: 46d235d0
Fault Module Name: fontext.dll
Fault Module Version: 6.0.6000.16386
Fault Module Timestamp: 4549d272
Exception Code: c0000005
Exception Offset: 0000000000009ab6
OS Version: 6.0.6000.2.0.0.768.3
Locale ID: 1033
Additional Information 1: 6aa0
Additional Information 2: 34c3d040364de78da0da3e46b23e7341
Additional Information 3: eb93
Additional Information 4: c25354b5dd62e1ecd873493c7f39af8d

Extra information about the problem
Bucket ID: 648675

What can I do???
Thank You.