how install toast lite 6.1 on mac os 10.9.4

It's too old to be installed past Snow Leopard (10.6).

Get Toast 10 or 11.

Never had version 10 myself, but it was reported to be pretty buggy. I've been using version 11 since it came out and have had no issues with it. Version 12 is current, but basically adds nothing worth mentioning, and costs far more than what you can get version 11 for. Unless you have a use for the shovelware they add to the Pro version, don't waste your money on it.

I see Corel (who now owns the title) has jumped the price of version 11 from about $57 to $73 most places you look. B&H Video of New York still has it for $60. That's what you used to be able to get it for at Amazon.

I've been using Toast 10 for several years and no issues. Presently using with Mavericks and no issues.

Good to hear. I had no direct experience with version 10 (tend to skip upgrade versions). As per normal I would guess, you read lots of negative reviews, but like here, you don't hear from the vast majority of users who aren't having problems.