Project built on Flex 3 was migrated to Flex 4. Now, every time the Project is built, the 'Building workspace' turns up and the continues upto 27% and then the IDE hangs.(this % value sometimes increases to 47%)..
Now, the same project, when built on Flex3, builds super quick.
I am running Flash builder 4 on Windows XP,SP3, 2GB RAM,AMD Athlon Dual Core processer (if this helps.. )