I got the above error while launching my Adobe Dreamweaver CS5.5. This is coming because of corrupted .txt file that DM looks at startup. File: “C:\Users\dyadav\AppData\Roaming\Adobe\Dreamweaver CS5.5\en_US\Configuration\Workspace\current.txt”
The text of file current.txt file should be “Designer.xml” but some how it was changed to “App Developer.xml” (most prob due to force reboot when DW got hanged). So I changed the text to “Designer.xml” and launched the DW again, and it worked this time !!