Error in Attribute value of build xml

Question

I am getting an error for the following code:

 <?xml version="1.0"?>
<!--
***************Demo.build******************
-->

<project name="Mybuild">
<include buildfile="config.xml" />

 <target name="build_my_solution">
 <mkdir dir="C:\Done" />
 <exec program="${NAntBuildPath}" output="${dir}>
  <arg line="${solution_file}" >
  <arg line="/property:Configuration=Release;AllowUnsafeBlocks=true" />
  <arg value="/target:Rebuild" />
  <arg value="/verbosity:normal" />
  <arg value="/nologo" />
  <arg value="/maxcpucount:2" /> 

  </exec>
  </target>
  </project>

ERROR(In Internet Explorer): The character '<' cannot be used in an attribute value. Error processing resource 'file:///C:/xxx/MyProject/...

-^

Answer 1

You are missing a closing quote mark in the exec element. It should be

<exec program="${NAntBuildPath}" output="${dir}"> 

Furthermore, the following arg element is not closed correctly. It should be

<arg line="${solution_file}" />

If you make these two changes, you should end up with well formed XML.