File Column issue

Hi All,
I’m using file_column_field for uploading the images it’s working
fine.But it throws random error as shown below.
<%= file_column_field(“ad”,“ad_picture”)%>
I’m using like this,but while uploading or editing the
image it throws an error randomly:
undefined method : ad_picture_temp forAd:#Object
i think this issue is comes while creating the file column
temporary(temp) object.
It occurs randomly.In single port its working fine,but i
configured in multiple port but it throws an error randomly.
Can someone please help on this?
Thanks in Advance…