can not config more tasks

[zhipenglin]

can not config more path
browserify:{
files:[{
expand: true,
cwd: 'coffee/src',
src: '/*.coffee',
dest: 'bin',
ext: '.js'
},{
expand: true,
cwd: 'tpl',
src: '/*.html',
dest: 'bin',
ext: '.js'
}],
options: {
transform: ['coffeeify','node-underscorify']
}
}
run:Running "browserify:files" (browserify) task
Warning: undefined is not a function Use --force to continue.

and can not config more tasks:
browserify:{
task_1:{
files:{
expand: true,
cwd: 'coffee/src',
src: '/*.coffee',
dest: 'bin',
ext: '.js'
}
},
task_2:{
files:{
expand: true,
cwd: 'tpl',
src: '/*.html',
dest: 'bin',
ext: '.js'
}
},
options: {
transform: ['coffeeify','node-underscorify']
}
}
run:Running "browserify:task_1" (browserify) task
Warning: undefined is not a function Use --force to continue.