All table elements must have columns specified; all columns must have column-width defined.
For example, this XSL-FO will generate a strict formatting error, because there are no columns:
<?xml version="1.0" encoding="utf-8"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
<fo:layout-master-set>
<fo:simple-page-master master-name="all-pages" page-width="8.5in" page-height="11in">
</fo:simple-page-master>
<fo:page-sequence-master master-name="default-sequence">
<fo:repeatable-page-master-reference master-reference="all-pages"/>
</fo:page-sequence-master>
</fo:layout-master-set>
<fo:page-sequence master-reference="default-sequence">
<fo:flow flow-name="xsl-region-body" font-size="12pt" font-family="Times New Roman">
<!-- table layout not specified, will default to 'auto' which leads to slower processing -->
<fo:table>
<!-- no columns specified, must do automatic layout which is a huge performance penalty -->
<fo:table-body>
<fo:table-row>
<fo:table-cell>
<fo:block>cell text</fo:block>
</fo:table-cell>
</fo:table-row>
</fo:table-body>
</fo:table>
</fo:flow>
</fo:page-sequence>
</fo:root>
The following XSL-FO will render fine:
<?xml version="1.0" encoding="utf-8"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
<fo:layout-master-set>
<fo:simple-page-master master-name="all-pages" page-width="8.5in" page-height="11in">
</fo:simple-page-master>
<fo:page-sequence-master master-name="default-sequence">
<fo:repeatable-page-master-reference master-reference="all-pages"/>
</fo:page-sequence-master>
</fo:layout-master-set>
<fo:page-sequence master-reference="default-sequence">
<fo:flow flow-name="xsl-region-body" font-size="12pt" font-family="Times New Roman">
<!-- table layout must be specified as 'fixed' -->
<fo:table table-layout="fixed">
<!-- columns specified, everything is ok -->
<!-- also don't forget to specify column width! -->
<fo:table-column column-width="proportional-column-width(1)"/>
<fo:table-column column-width="proportional-column-width(1)"/>
<fo:table-body>
<fo:table-row>
<fo:table-cell>
<fo:block>cell text</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>cell text</fo:block>
</fo:table-cell>
</fo:table-row>
</fo:table-body>
</fo:table>
</fo:flow>
</fo:page-sequence>
</fo:root>