I hate doing long post so I have put a few links which might help you in the migration from iis 6 to iis 7.
Resources you might look into.
Migrate a Web Site from IIS 6.0 to IIS 7 or above [learn.iis.net]
Troubleshooting Common MSDeploy Issues [blogs.iis.net]
Configuring IIS to Run 32-bit Applications on 64-bit Windows [blog.dczweb.net]