sounds like you may have moved the locations of the files and SSL cant find them now.. just reimport them

i have deleted my all folder and reinstalled it and still the same thing. all my files are in one folder

You deleted all the songs in your All folder and then reimported all the songs back into Scratch LIVE? What about the crates?

Make sure you don't have 2 of the same tracks imported (i.e one good and one missing)

Rescanning the tags is a handy way to identify all the files that Scratch LIVE can’t find (for example if the files have been altered or moved). These tracks will show up red in the main track list, with an exclamation mark in the status column. You can sort by the status column to group all these tracks together and then delete them with ease.

i am going to try and start from scratch and see if things work fine