I figured out the issue here. I always assumed I had mines on Earth because on the Mining/Maintenance screen it indicates "100 Ground-based mines." However, it appears those 100 ground based mines are actually being generated from conventional industry.  It appears I will need to convert them to proper mines! Thanks for attempting to help!

So I've been using civilian contracts effectively for my game and all has been well. I create supply contracts at a location that has a specific installation and then create a demand contract at a place that needs that installation. The civilian ships come and dutifully transport said installation to the destination. However, I recently decided it was time to move manned mines from Earth and move them to Mars.  I have a colony and a large population and Mars and have used civilian contracts to move manned mines to Mars previously earlier in the game. However, this time when I created the contract and advanced time a bunch of events were generated indicating loading problems and simply that many civilian ships failed to load the installation at Earth.

I have no idea why this is happening.  Any thoughts/suggestions? Thanks!