Is this a temporary domain name? Often, problems with those go away once the "real" domain name is substituted.
There could also be a problem with the ownership of the core/packages directory.
Console running... Attempting to install package with signature: getpage-1.2.3-pl Package found...now preparing to install. Target directory is either not a directory or writable: /home/content/54/8603754/html/core/packages/ Could not transfer package getpage-1.2.3-pl.transport.zip to /home/content/54/8603754/html/core/packages/. Could not install package with signature: getpage-1.2.3-pl