WPMUDEV Dashboard not allowing plugins to update

Whenever I try to use the WPMUDEV dashboard to either update a plugin, or install a new plugin, I get the following (or very similar) error:
"The package could not be installed. PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature"

Any suggestions as to what might be happening and what can be done to resolve it would be appreciated.

Thanks!