I have grown Blue Lake many times - and am going to have them again this year. What I have found, however, is that the seed really doesn't keep well, whether it is saved from last year's plants or leftover seed in the packet. I don't know why - but, a bit like parsnip seed, it is best to have fresh seed each year.
If you got these at a plant seed swap, they were probably old/surplus seed. I think I would buy some fresh and start again. They ought to germinate within a few days, so I think yours are duds, I regret to say.
For the record, I found that they are lovely and prolific French beans which have good taste and freeze well.