Double check you are using these exact items (versions) in your setup:
1) Sibelius 5.2.5 - You may need to be running the Sib 5.4 update for Mac OS 10.7.5, but I'm not sure. See http://www.sibelius.com/helpcenter/upgrades.html for compatibility notes and download links.
2) Virtual Drumline 2.5.2 - You're stuck with VDL 2.5.2 in Sib 5 since Kontakt Player 4 is the minimum required for VDL 2.5.5. When you finally do upgrade to VDL 2.5.5, you'll most likely be forced to upgrade Sibelius to version 7.1.3, which is OK since you'd be running the latest at that point anyway.
3) Kontakt Player 2 - The latest KP2 update that I know of is version 2.2.4. Neither KP4 nor KP5 are compatible with Sib 5.
4) VDL SoundSet 7.0a - This XML file ("VDL_SoundSet_7.0a.xml") goes in /Users/yourusername/Library/Application Support/Sibelius Software/Sibelius 5/Sounds.
5) "VDL_Template_7.0a.sib" - Until you create a new Manuscript Paper from this file, you won't see it when you create a File > New within Sibelius. Instructions for creating a Manuscript Paper in Sib 5 is on page 25 of the Readme. Another option is to make a copy of this file for each new writing project.
Remember that you'll not be able to use the new-to-2.5.5 template instrument definitions since you're not running that library version. Again, upgrading software will take care of that too.
If you still have troubles after all this, please attach screen shots of what you see, including shots of: your Playback Configuration, file system contents, and/or whatever else you think needs looking at. Oh, and you may want to read the Readme again, just in case.
Late
Hugh
1) Sibelius 5.2.5 - You may need to be running the Sib 5.4 update for Mac OS 10.7.5, but I'm not sure. See http://www.sibelius.com/helpcenter/upgrades.html for compatibility notes and download links.
2) Virtual Drumline 2.5.2 - You're stuck with VDL 2.5.2 in Sib 5 since Kontakt Player 4 is the minimum required for VDL 2.5.5. When you finally do upgrade to VDL 2.5.5, you'll most likely be forced to upgrade Sibelius to version 7.1.3, which is OK since you'd be running the latest at that point anyway.
3) Kontakt Player 2 - The latest KP2 update that I know of is version 2.2.4. Neither KP4 nor KP5 are compatible with Sib 5.
4) VDL SoundSet 7.0a - This XML file ("VDL_SoundSet_7.0a.xml") goes in /Users/yourusername/Library/Application Support/Sibelius Software/Sibelius 5/Sounds.
5) "VDL_Template_7.0a.sib" - Until you create a new Manuscript Paper from this file, you won't see it when you create a File > New within Sibelius. Instructions for creating a Manuscript Paper in Sib 5 is on page 25 of the Readme. Another option is to make a copy of this file for each new writing project.
Remember that you'll not be able to use the new-to-2.5.5 template instrument definitions since you're not running that library version. Again, upgrading software will take care of that too.
If you still have troubles after all this, please attach screen shots of what you see, including shots of: your Playback Configuration, file system contents, and/or whatever else you think needs looking at. Oh, and you may want to read the Readme again, just in case.
Late
Hugh