Hello,
In C:\Program Files\SAP\hdbstudio\tmp_*director*\director (the most recently created directory)
Change the -Xmx parameter from 1024 to 512 in the eclipse.ini config file
If this doesn't help you (as i also had problems with this)
Install a new SP07 studion and update it from your local filesystem as a repository to have SP 08. That will do the trick for sure.
BR,
Peter