When you try to open a document in Dreamweaver CS5 or CS5.5, it takes anywhere from 30 seconds to several minutes for Dreamweaver to open it. Dreamweaver stops responding until the document opens.
Solution: Disable the Resolve to IP Address feature
Disable Dreamweaver's Resolve To IP Address feature using the instructions for your operating system.
Disclaimer: These steps require you to modify the Windows registry, which contains critical information about your system and applications. Before modifying the registry, always make a backup copy of it. Adobe doesn't provide support for problems that arise from improperly modifying the registry. For information about the Windows registry, see the documentation in Windows or contact Microsoft Technical Support or your computer's manufacturer.
When you open documents that contain remote URI references in Dreamweaver, it contacts a DNS server to qualify each remote URI to its IP address. With some network configurations, it can take several seconds or longer, causing Dreamweaver to become unresponsive until it receives the response from the DNS server. If the document contains one or more invalid URIs, it can take longer to receive the response from the DNS server.