Problem mining Genesis Block in Dash Clone
I am not familiar with dash-coin, however, in my experience with cloning other coins (litecoin w/ scrypt PoW, bitcoin w/ SHA256) even with a few nodes running the client, I was unable to mine with an external mining software (like cpuminer) until 15-20th block was generated using the CLI. Either within the qt client console or using the coin-cli generate nblocks command. 

If you have successfully coded the genesis block into the source and were able to compile/run the client I would try using the generate command or whatever the equivalent is within the client.