/p>
<p><span class="fndoclabel">Errors</span> <br />The existing or supplied instance name of <var>instance</var> is
identical to the instance name of an existing <a href="ref-glossary.html#id256">unit&nbsp;instance</a> of
<var>new-class</var>.
</p>
<p><span class="fndoclabel">Description</span> <br />When <var>new-class</var> is a <a href="ref-glossary.html#id254">unit&nbsp;class</a>, an instance-name conflict with
an existing <a href="ref-glossary.html#id256">unit&nbsp;instance</a> of <var>new-class</var>