There is no build provider registered for the extension '.dll'.

There is no build provider registered for the extension '.dll'.

I'm trying to reference to a .dll file from a .aspx web page. However, I
get the following error:
Description: An error occurred during the parsing of a resource required
to service this request. Please review the following specific parse error
details and modify your source file appropriately.
Parser Error Message: There is no build provider registered for the
extension '.dll'. You can register one in the
<compilation><buildProviders> section in machine.config or web.config.
Make sure is has a BuildProviderAppliesToAttribute attribute which
includes the value 'Web' or 'All'.
Source Error:
Line 2: <%@ Page Title="" Language="C#"
MasterPageFile="CSharpBPTestMaster.master" AutoEventWireup="true"
CodeFile="CSharpBPTest.aspx.cs" Inherits="Button" Debug="true"%>
Line 3:
Line 4: <%@ Register tagprefix="blnc" tagname="Balanced"
src="bin/Debug/BalancedTest.dll" %>
Line 5:
Line 6:
Source File:
/preview/1/balanced-csharp-master/src/BalancedTest/CSharpBPTest.aspx
Line: 4
I'm not sure what I'm doing wrong. I build the .csproj file. I have the
following in bin\Debug\:
Balanced.dll
Balanced.pdb
BalancedTest.dll
BalancedTest.pdb
Here is my CSharpBPTest.aspx:
<%@ Page Title="" Language="C#"
MasterPageFile="CSharpBPTestMaster.master" AutoEventWireup="true"
CodeFile="CSharpBPTest.aspx.cs" Inherits="Button" Debug="true"%>
<%@ Register tagprefix="blnc" tagname="Balanced"
src="bin/Debug/BalancedTest.dll" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1"
Runat="Server">
<form id="form1" runat="server">
<div>
<asp:Button ID="button1" runat="server" Text="Submit"
OnClick="Button_Command"/>
<br />
<br />
<br><asp:label id="warningLabel" Text="" ForeColor="Red"
runat="server"/><br>
<br />
</div>
</form>
</asp:Content>
And in my C# file, I "import" the project like this (at the top):
using Balanced;
I want to be able to use this compiled .dll file on my C# side. The
Balanced.dll is an external library. It just came with the files and a
.csproj file. I did a build and now I'm trying to use this Balanced.dll
file. Am I missing something? I'm sorry if this is a bad question. I'm new
to asp.net and csproj.