If your MiniProg3 failed and you open a Technical Support case on the website, we should be able to get a new one sent out to you.
This is not issue with MiniProg3. I have faced this issue earlier. I guess you are using Miniprog3 as USB-I2C bridge and trying to communicate with a PSoC3. The main problem here is the I2C bus connection. Due to loose contacts it is possible that the devices listed on the I2C bus are more than one. Establish a firm connection by some means(sodering ), that may fix this issue.