Validating my XML using DTD

[fischbone]

I need some serious help validating my XML using DTD. Can someone look at this and lead me in the right direction? I am completely new to XML and cannot figure out what I am doing wrong. When I put the code in the validator, I keep getting the error: element content is invalid according to dtd schema. I have know idea what's going on.

<?xml version="1.0" ?> 
<!DOCTYPE document[
<!ELEMENT document (tableofcontents,content)>
<!ELEMENT tableofcontents (part|pagenumber|subpart)+> 
<!ELEMENT part (#PCDATA)>
<!ELEMENT pagenumber (#PCDATA)>
<!ELEMENT subpart (#PCDATA)>
<!ELEMENT content (title|subtitle|pageone|pagetwo|pagethree|pagefour|pagefive|pagesix|pageseven)+>
<!ELEMENT title (#PCDATA)>
<!ELEMENT subtitle (#PCDATA)>
<!ELEMENT pageone (#PCDATA)>
<!ELEMENT pagetwo (#PCDATA)>
<!ELEMENT pagethree (#PCDATA)>
<!ELEMENT pagefour (#PCDATA)>
<!ELEMENT pagefive (#PCDATA)>
<!ELEMENT pagesix (#PCDATA)>
<!ELEMENT pageseven (#PCDATA)>
<!ELEMENT references (#PCDATA)>
<!ATTLIST document type CDATA #IMPLIED>
<!ENTITY cr "Copyright (C) 2011 XXXXXXX">
]>

[fischbone]

Here's the rest of the code. I couldn't fit it in the same post.

<document>
  <tableofcontents>
	<part>INTRODUCTION</part>
    <pagenumber>1</pagenumber>
	<part>A BRIEF HISTORY OF SOCIAL MEDIA</part>
    <pagenumber>1</pagenumber>
	<part>THE ROLE OF SOCIAL MEDIA IN BUSINESS</part>
    <pagenumber>2</pagenumber>
	   <subpart>Social Networking Functions</subpart>
	<pagenumber>3</pagenumber>
    <part>IMPLEMENTING A SOCIAL MEDIA BUSINESS STRATEGY</part>
    <pagenumber>4</pagenumber>
	  <subpart>Determining Our Objective</subpart>
	<pagenumber>4</pagenumber>
	  <subpart>Department That Runs Social Media</subpart>
	<pagenumber>4</pagenumber>
	  <subpart>Consider Employees</subpart>
	<pagenumber>4</pagenumber>
	  <subpart>Check Technology</subpart>
	<pagenumber>4</pagenumber>
	  <subpart>Listen First</subpart>
	<pagenumber>5</pagenumber>
	<part>DISCUSSION:  REVENUES AND BENEFITS</part>
    <pagenumber>5</pagenumber>
	<subpart>Revenues</subpart>
	<pagenumber>5</pagenumber>
	<subpart>Projections</subpart>
	<pagenumber>6</pagenumber>
	<subpart>Trends</subpart>
	<pagenumber>6</pagenumber>
	<part>CONCLUSION AND RECOMMENDATIONS</part>
    <pagenumber>7</pagenumber>
	<part>REFERENCES</part>
    <pagenumber>8</pagenumber>
</tableofcontents>
<content>
 <title>INTRODUCTION</title><pageone></pageone>
 

<pagetwo><title>THE ROLE OF SOCIAL MEDIA IN BUSINESS</title>

<pagethree><title>Social Networking Functions</title> 
.</pagethree> 


<pagefour><title>IMPLEMENTING A SOCIAL MEDIA BUSINESS STRATEGY</title>

 <subtitle>Department That Runs Social Media</subtitle>

<pagefive><title>DISCUSSION:  REVENUES AND TRENDS</title>
 
<subtitle>Revenues</subtitle>

</pagefive>
<pagesix><subtitle>Projections</subtitle>

<subtitle>Trends</subtitle>
 </pagesix>

<pageseven><title>CONCLUSIONS AND RECOMMENDATIONS</title>
</pageseven> 
</content>
<references>
<title>REFERENCES</title>

</references>
</document>