Reading some of these posts, you can make problems for yourselves if you insist on playing the original lines note for note on every occasion. If you really have to play a line and you can't, then the only answer is to practice it until you can!
If I'm learning a song, I check the original version, then I have a look for the original band playing live. Many times they aren't even playing the original lines themselves. I work out what needs to be kept and what I can add. I make sure I capture the gist, the feel and flavour of the original but I'm the player. It's perfectly acceptable to make these songs your own.