Eric White's Blog

What you are looking for is the Pane class. Vincent Tan describes it below:

Freezing is easier to understand than splitting For both freezing and splitting panes, you’ll be working with the Pane class. Specifically, you’ll be assigning values to the HorizontalSplit and VerticalSplit properties (it’s still these 2 properties for freezing, despite the name of the properties).
Now for freezing panes, you simply assign the number of left-most columns and top-most rows to the HorizontalSplit and VerticalSplit properties respectively. For example, if you want to freeze the first 3 columns, just assign 3 to HorizontalSplit. Splitting panes is a little more complicated. For splitting, the HorizontalSplit and VerticalSplit properties take on different values than with freezing. From the Open XML SDK documentation:
Horizontal position of the split, in twentieths of a point; 0 if none. If the pane is frozen, this value indicates the number of columns visible in the top pane.
and
Vertical position of the split, in twentieths of a point; 0 if none. If the pane is frozen, this value indicates the number of rows visible in the left pane.
From my investigations, it’s not a simple “find width/height in point units then multiply by 20”.

I can offer debugging suggestions, but do not have Open XML loaded to be able to do what I will be telling you to do.

The Open XML SDK 2.5 has the ability to use reflection to expose the XML used in an Excel spreadsheet. Build the spreadsheet you are trying to build with Open XML and access it through the tool. What it will show is the proper order of the XML you are trying to create in Open XML. This would be the most likely problem causing the created Excel spreadsheet not to open. Below is a list from Vincent Tan’s book:

// OpenXML Sheet Object Attachment Order
<complexType name=”CT_Worksheet”>
<sequence>
<element name=”sheetPr”/>
<element name=”dimension”/>
<element name=”sheetViews”/>
<element name=”sheetFormatPr”/>
<element name=”cols”/>
<element name=”sheetData”/>
<element name=”sheetCalcPr”/>
<element name=”sheetProtection”/>
<element name=”protectedRanges”/>
<element name=”scenarios”/>
<element name=”autoFilter”/>
<element name=”sortState”/>
<element name=”dataConsolidate”/>
<element name=”customSheetViews”/>
<element name=”mergeCells”/>
<element name=”phoneticPr”/>
<element name=”conditionalFormatting”/>
<element name=”dataValidations”/>
<element name=”hyperlinks”/>
<element name=”printOptions”/>
<element name=”pageMargins”/>
<element name=”pageSetup”/>
<element name=”headerFooter”/>
<element name=”rowBreaks”/>
<element name=”colBreaks”/>
<element name=”customProperties”/>
<element name=”cellWatches”/>
<element name=”ignoredErrors”/>
<element name=”smartTags”/>
<element name=”drawing”/>
<element name=”legacyDrawing”/>
<element name=”legacyDrawingHF”/>
<element name=”picture”/>
<element name=”oleObjects”/>
<element name=”controls”/>
<element name=”webPublishItems”/>
<element name=”tableParts”/>
<element name=”extLst”/>
</sequence>
</complexType>

// OpenXML Workbook Object child xml order
FileSharing <x:fileSharing>
WorkbookProperties <x:workbookPr>
WorkbookProtection <x:workbookProtection>
BookViews <x:bookViews>
Sheets <x:sheets>
FunctionGroups <x:functionGroups>
ExternalReferences <x:externalReferences>
DefinedNames <x:definedNames>
CalculationProperties <x:calcPr>
OleSize <x:oleSize>
CustomWorkbookViews <x:customWorkbookViews>
PivotCaches <x:pivotCaches>
SmartTagProperties <x:smartTagPr>
SmartTagTypes <x:smartTagTypes>
WebPublishing <x:webPublishing>
FileRecoveryProperties <x:fileRecoveryPr>
WebPublishObjects <x:webPublishObjects>
WorkbookExtensionList <x:extLst>

It isn’t the only possibility. Others include not keeping table names unique, using sheet order instead of sheet id order, forgetting to attach sheets to sheetparts (etc) and others. I will do some research and try to find the order that sheetview fits into.