I strongly advise to NOT use MediaTemple unless you have godlike Linux skills and serious IT resources for time wasting.
Mediatemple configures their Apache service in as a different user from the WordPress. Thus, when you upload from WordPress it attempts to write to directories that have been created by Apache. And because because they are not owned in the same group you cannot write over them.While this can be 'foxed' by changing permissions to 777 you create security concerns.
Media Temple have proposed a solution using fast CGI, however this causes serious memory exhaustion problems and stability issues - at just five thousand hits per day by systems my (dv) instance is running at 70% CPU. Worse, after implementing this recommended change for FastCGI, I need to reboot twice per day to keep the system running at reasonable speed.
Media Temple tech support refuse to offer any assistance, at any time or for any purpose with relationship to WordPress. Additionally if you attempt to use support by e-mail it will take between one and three days for a response to occur-and because I am overseas I cannot use the telephone.
Again strongly to recommend you DO NOT use media Temple for any purpose.