If you think, it is a problem of Sikuli (and not only the case, that Sikuli cannot find the given shot on the screen), then run the ide command with options d:3 -c and have a look at the debugging information.
If you think, it is a problem of Sikuli (and not only the case, that Sikuli cannot find the given shot on the screen), then run the ide command with options d:3 -c and have a look at the debugging information.