XML's are just not my thing!
<?xml version="1.0" standalone="yes"?>
<System>
<Body>
<Name>Sun</Name>
<Object>Sun</Object>
<Appearance>Sun</Appearance>
<Mass>19891000000</Mass>
<Density>1.40844628708309</Density>
<Diameter>1392000</Diameter>
<PositionX>-67885734.9754417</PositionX>
<PositionY>129233872.55859</PositionY>
<PositionZ>20395297.0298883</PositionZ>
<VelocityX>6.1834716256905E-08</VelocityX>
<VelocityY>-2.6114950594118E-08</VelocityY>
<VelocityZ>-9.34240494717165E-09</VelocityZ>
<Settings>gravity=1</Settings>
<Action>belt=sma:4.519 au, smarange:1.2 au, count:10000, h:0.5
</Body>
<Body>
<Name>Yyrak</Name>
<Texture>test3.jpg</Texture>
<Mass>2.729 jupiters</Mass>
<Diameter>347501.06</Diameter>
<Orbit>body=Sun</Orbit>
<Orbit>a=5.3918087 au</Orbit>
<Orbit>e=0.0014782</Orbit>
<Orbit>i=1.4829102</Orbit>
<Orbit>node=209.72</Orbit>
<Orbit>peri=128.49</Orbit>
<Settings>timestep=1.00 minute</Settings>
</Body>
<Body>
<Name>Tempest</Name>
<Object>Earth</Object>
<Mass>1.173482 earths</Mass>
<Diameter>23098 km</Diameter>
<Orbit>body=Sun</Orbit>
<Orbit>a=0.9934117</Orbit>
<Orbit>e=0.0189473</Orbit>
<Orbit>i=0.9764071</Orbit>
<Orbit>node=100.08</Orbit>
<Orbit>peri=101.48</Orbit>
<Settings>focus=Tempest</Settings>
</Body>
<Body>
<Name>Nalipax</Name>
<Object>Uranus</Object>
<Mass>13.5892012 earths</Mass>
<Diameter>1454098 km</Diameter>
<Orbit>body=Sun</Orbit>
<Orbit>a=12.141113</Orbit>
<Orbit>e=0.0448772</Orbit>
<Orbit>i=0.0183708</Orbit>
<Orbit>node=23.991</Orbit>
<Orbit>peri=341.72</Orbit>
</Body>
<Body>
<Name>Xzyrr</Name>
<Object>Europa</Object>
<Mass>0.7938 earths</Mass>
<Diameter>14272 km</Diameter>
<Orbit>body=Sun</Orbit>
<Orbit>a=15.34987</Orbit>
<Orbit>e=0.0934875</Orbit>
<Orbit>i=1.0013478</Orbit>
<Orbit>node=344.89</Orbit>
<Orbit>peri=121.17</Orbit>
</Body>
</System>
I also tried <Object> as <Appearance>, I also checked for misspells quickly, and didn't find anything. Though, you may still want to check.