DropDownList in a custom form control gives 'DropDownList' must be placed inside a form tag with runat=server

<div class="post-text" itemprop="text"> We are using a custom form control in our application. When we try to use asp dropdownlist control inside this custom form control, I get this given exception. But, when I use asp literal control we don't get this error.
Please suggest if you can provide me any directions in which to look to fix this issue.
Tks, Puneet Jain
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