Your "S-Christmas Lights" scene has a link to your "Leak Sensors" folder, I'm not sure how or if that's intentional, but my guess is that's whats causing it to choke:
<group flag="132" nodeDefId="InsteonDimmer">
<address>15887</address>
<name>S-Christmas Lights</name>
<family>6</family>
<hint>0.0.0.0</hint>
<parent type="3">47955</parent>
<deviceGroup>29</deviceGroup>
<pnode>15887</pnode>
<members>
<link type="0">ZY076_1</link>
<link type="0">ZY077_1</link>
<link type="0">37 C7 69 1</link>
<link type="0">35 53 E5 1</link>
<link type="16">3D 7A 77 8</link>
<link type="0">51393</link>
</members>
</group>
<folder flag="0">
<address>51393</address>
<name>Leak Sensors</name>
<family>13</family>
<hint>0.0.0.0</hint>
<parent type="3">53032</parent>
</folder>
