The test for '' after getting the location into BaseDir should test BaseDir not BaseURL.

packages/fcl-web/src/base/fpwebfile.pp

@@ -343,7 +343,7 @@ begin
   else
     begin
     BaseDir:=Locations.Values[BaseURL];
-    if (BaseURL='') then
+    if (BaseDir='') then
       BaseDir:=ExtractFilePath(Paramstr(0))
     end;
   FN:=ExtractRelativepath(BaseDir,aFileName);