Hi,
you have to provide the correct database schema, the table and the id of the data in the CMS_RENDER tag.
For example:
ContentSelection:
<CMS_FUNCTION name="contentSelect" resultname="cs_press_releases">
<CMS_PARAM name="schema" value="Products" />
<QUERY entityType="Press_Releases">
<ORDERCRITERIA attribute="Date" descending="1" />
</QUERY>
</CMS_FUNCTION>
$CMS_FOR(press_release, cs_press_releases)$
$CMS_RENDER(template:"WEBeditInplaceEditBegin", content:"Products.press_releases", index:press_release.getId())$
...
$CMS_RENDER(template:"WEBeditInplaceEditEnd")$
$CMS_END_FOR$