I was referring to your utility since it seems handy. I've tried it under mono as well, with proper dependencies (window.forms.dll, etc.) It launches fine & reaches the ToC editor. But using the 'fix margins' option triggers a crash :S
(I know I should've reported it, but I assume it must be some quirk with my system.)
Vague back-trace:
Spoiler:
$ mono ./ePubFixer\ v1.5/ePubFixer.exe
[After hitting Go for margin fix]
System.ArgumentNullException: Argument cannot be null.
Parameter name: rawAssembly
at System.AppDomain.Load (System.Byte[] rawAssembly, System.Byte[] rawSymbolStore, System.Security.Policy.Evidence securityEvidence, Boolean refonly) [0x00000] in <filename unknown>:0
at System.AppDomain.Load (System.Byte[] rawAssembly, System.Byte[] rawSymbolStore, System.Security.Policy.Evidence securityEvidence) [0x00000] in <filename unknown>:0
at (wrapper remoting-invoke-with-check) System.AppDomain:Load (byte[],byte[],System.Security.Policy.Evidence)
at System.AppDomain.Load (System.Byte[] rawAssembly) [0x00000] in <filename unknown>:0
at (wrapper remoting-invoke-with-check) System.AppDomain:Load (byte[])
at System.Reflection.Assembly.Load (System.Byte[] rawAssembly) [0x00000] in <filename unknown>:0
at ePubFixer.Program.Resolver (System.Object sender, System.ResolveEventArgs args) [0x00000] in <filename unknown>:0
at System.AppDomain.DoAssemblyResolve (System.String name, Boolean refonly) [0x00000] in <filename unknown>:0
at ePubFixer.frmMain.<UpdateFiles>b__0 (ePubFixer.Document x) [0x00000] in <filename unknown>:0
at System.Collections.Generic.List`1[ePubFixer.Document].ForEach (System.Action`1 action) [0x00000] in <filename unknown>:0
at ePubFixer.frmMain.UpdateFiles () [0x00000] in <filename unknown>:0
at ePubFixer.frmMain.btnGo_Click (System.Object sender, System.EventArgs e) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Control.OnClick (System.EventArgs e) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Button.OnClick (System.EventArgs e) [0x00000] in <filename unknown>:0
at System.Windows.Forms.ButtonBase.OnMouseUp (System.Windows.Forms.MouseEventArgs mevent) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Button.OnMouseUp (System.Windows.Forms.MouseEventArgs mevent) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Control.WmLButtonUp (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Control.WndProc (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0
at System.Windows.Forms.ButtonBase.WndProc (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Button.WndProc (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Control+ControlWindowTarget.O nMessage (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0
at System.Windows.Forms.Control+ControlNativeWindow.W ndProc (System.Windows.Forms.Message& m) [0x00000] in <filename unknown>:0
at System.Windows.Forms.NativeWindow.WndProc (IntPtr hWnd, Msg msg, IntPtr wParam, IntPtr lParam) [0x00000] in <filename unknown>:0