Commented Unassigned: Loading a new workbook fails under mono [9413]

I am unable to do one of the most basic things, open a new workbook under Ubuntu running monodevelop. The following code:
```
XLWorkbook wb = new XLWorkbook("input.xlsx");

```
throws an exception:

```
System.IO.IOException: Operation not valid when package is read-only
at System.IO.Packaging.Package.CheckIsReadOnly () [0x00000] in <filename unknown>:0
at System.IO.Packaging.PackagePart.CreateRelationship (System.Uri targetUri, TargetMode targetMode, System.String relationshipType, System.String id, Boolean loading) [0x00000] in <filename unknown>:0
at System.IO.Packaging.PackagePart.LoadRelationships (System.Collections.Generic.Dictionary`2 relationships, System.IO.Stream stream) [0x00000] in <filename unknown>:0
at System.IO.Packaging.PackagePart.get_Relationships () [0x00000] in <filename unknown>:0
at System.IO.Packaging.PackagePart.GetRelationships () [0x00000] in <filename unknown>:0
at DocumentFormat.OpenXml.Packaging.PackagePartRelationshipPropertyCollection..ctor (System.IO.Packaging.PackagePart packagePart) [0x00000] in <filename unknown>:0
at DocumentFormat.OpenXml.Packaging.OpenXmlPart.Load (DocumentFormat.OpenXml.Packaging.OpenXmlPackage openXmlPackage, DocumentFormat.OpenXml.Packaging.OpenXmlPart parent, System.Uri uriTarget, System.String id, System.Collections.Generic.Dictionary`2 loadedParts) [0x00000] in <filename unknown>:0
at DocumentFormat.OpenXml.Packaging.OpenXmlPartContainer.LoadReferencedPartsAndRelationships (DocumentFormat.OpenXml.Packaging.OpenXmlPackage openXmlPackage, DocumentFormat.OpenXml.Packaging.OpenXmlPart sourcePart, DocumentFormat.OpenXml.Packaging.RelationshipCollection relationshipCollection, System.Collections.Generic.Dictionary`2 loadedParts) [0x00000] in <filename unknown>:0
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.Load () [0x00000] in <filename unknown>:0
```

The file has all rwx permissions. Is Linux not supported somehow? Am I making some n00b mistake?

Comments: There is a possible bug in Mono http://lists.ximian.com/pipermail/mono-bugs/2011-February/109577.html In another project there's an issue very similar to ours trying to use the OpenXML 2.5 library calling C# from Javascript through a thing called Edge.js (this is what I'm actually trying to do as well) https://github.com/OfficeDev/Open-XML-SDK/issues/39 I've forked the repo and am experimenting with changing the call to SpreadsheetDocument.Open to use FileAccess.ReadWrite instead of FileAccess.Read.