Can you assist in helping me successfully install the Spirit theme using the WPMU Dev Dashboard?

I'm using InstantWP_4.2 a standalone application in which to create my website. I've successfully installed the WPMU DEV Dashboard and Spirit is appearing in the Themes listing; however, when I try to install it, I receive the following error message: “Download failed. SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed”.

Can you assist in resolving this problem?
Thank you!