Error 500 when deleting an Image

I’m following the YOUTUBE WAPPLER tutorial about “Creating an Image Gallery”. All is running pretty well but, when I arrived at video number 21 and I pressed the delete button in the photo (in this case is a button with an “X” ) the following error appears: "Failed to load resource: the server responded with a status of 500 " this refered to server actions file “imgBaixa.php”.

I’ve tested de error through the error file and this is what appears:

(This is not true the folder galeries and the gallery name 11 exists)

|trace|"#0 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/lib/App.php(173): modules\fs->remove(Object(stdClass), ‘FotoGranBaixa’)\n#1 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/lib/App.php(107): lib\App->execSteps(Object(stdClass))\n#2 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/modules/fs.php(51): lib\App->exec(Object(stdClass), true)\n#3 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/lib/App.php(173): modules\fs->exists(Object(stdClass), ‘fileExists1’)\n#4 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/lib/App.php(137): lib\App->execSteps(Object(stdClass))\n#5 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/lib/App.php(107): lib\App->execSteps(Array)\n#6 /Applications/MAMP/htdocs/Wapgaleries/dmxConnectLib/lib/App.php(72): lib\App->exec(Object(stdClass))\n#7 /Applications/MAMP/htdocs/Wapgaleries/dmxConnect/api/Imatges/ImgBaixa.php(8): lib\App->define(Object(stdClass))\n#8 {main}"|