the resource is not on the build path of a php project

<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
    <name>wmsadminapi</name>
    <comment></comment>
    <projects>
    </projects>
    <buildSpec>
        <buildCommand>
            <name>org.eclipse.wst.validation.validationbuilder</name>
            <arguments>
            </arguments>
        </buildCommand>
        <buildCommand>
            <name>org.eclipse.dltk.core.scriptbuilder</name>
            <arguments>
            </arguments>
        </buildCommand>
        <buildCommand>
            <name>org.eclipse.wst.common.project.facet.core.builder</name>
            <arguments>
            </arguments>
        </buildCommand>
    </buildSpec>
    <natures>
          <nature>org.eclipse.php.core.PHPNature</nature>
        <nature>org.eclipse.wst.common.project.facet.core.nature</nature>
        <nature>net.sourceforge.phpeclipse.phpnature</nature>
    </natures>
</projectDescription>