There two limitations for tables: 1) FOP needs you to explicitly specify column widths
2) Cells have to contain block-level FOs. They can't contain straight character data.
A working basic example of a table looks like this:
<fo:table>
<fo:table-column column-width="150pt"/>
<fo:table-column column-width="150pt"/>
<fo:table-body font-size="10pt" font-family="sans-serif">
<fo:table-row>
<fo:table-cell>
<fo:block>text</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>text</fo:block>
</fo:table-cell>
</fo:table-row>
<fo:table-row>
<fo:table-cell>
<fo:block>text</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>text</fo:block>
</fo:table-cell>
</fo:table-row>
<fo:table-row>
<fo:table-cell>
<fo:block>text</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>text</fo:block>
</fo:table-cell>
</fo:table-row>
</fo:table-body>
</fo:table>