It's strongly advisable that WinBuilder works in (C:\) partition (otherwise bluescreens @boot are frequent).D:\Winbuilder_VistaPE11\Target\VistaPE Beta\Windows\system32\bcdedit.exe was not found. bla bla bla...
Furthermore (if you do not already solved), please copy "bcdedit.exe" in "System Root\System32" and see what happen... you never know!