注意：在localhost上安装couponic时，数组到字符串转换

I'm trying to install couponic on localhost, but i got many errors. This is one of that errors. Here is the code which that error shows.

public function cacheKey()
{
    $cacheKey = 'UniProgy.UWorkletConstructor.' . $this->id;
    reset($this->filters);
    foreach($this->filters as $obj)
        if($addCacheKey = $obj->cacheKey($this->id))
            $cacheKey.= '.' . $addCacheKey;
    return $cacheKey;
}

Can anyone help me to solve this problem?

Thanks,

When i make it like this it's working perfectly.

public function cacheKey()
{
    $cacheKey = 'UniProgy.UWorkletConstructor.' . $this->id;
    reset($this->filters);
    foreach($this->filters as $obj){
        if($addCacheKey = $obj->cacheKey($this->id)){
            $cacheKey.= '.' . $addCacheKey;
    }
    return $cacheKey;
   }
}