I wouldn't recommend any kind of string lube on nylon strings. Have you played with lotion on your hands, or something? That could make the strings sticky. I would wipe the strings down with a damp (not wet) rag and if that doesn't do the job maybe try just a dab of rubbing alcohol on a rag. (Note, be cautious here because some fretboards are "ebonized" with a dye and the alcohol might remove or smear it.)
If you use lotions or have sweaty hands, or if you've been working with chemicals, oils, etc., you should wash your hands before playing.
Keep in mind that, except when barring more than one string with a single finger, only the very tip of your finger should touch the string. Lift your fingers straight up. Lots of times people don't realize that they're pulling laterally against the string when they lift their fingers. This is sometimes done intentionally (called a pull off) but lots of times beginners do it all the time without realizing it.
Finally, as a last resort you might try a bit of talcum powder (or pool cue chalk) on your fingertips before playing. Be advised that this can work its way into the grain of the wood on the fretboard but it beats not being able to play the uke!
John
And that's a sweet Uke you have! :drool:
