Some VBA macros in a spreadsheet processed by ExcelWriter or WordWriter fail to execute when the file is opened in Internet Explorer. However, if the file is saved to the local filesystem and opened afterwards in Excel or Word, the macro works fine.
This issue is with MS Office and Internet Explorer, not with OfficeWriter. OfficeWriter preserves all VBA macros when processing a spreadsheet or document. However, not all VBA will execute in the Excel or Word browser plug-ins. In order to guarantee that all your macros will run in your OfficeWriter-generated files, it is recommended to use the Save option that will open the file in a separate Excel or Word window rather than in the browser.
For more information, see this article: Some Macro Commands Are Not Run in MS Internet Explorer.
To make sure that your OfficeWriter-generated files are opened in Excel or Word instead of the browser, specify ‘false’ when using the Save method:
xlt.Save(Page.Response, "WorkbookWithMacros_out.xlsm", false); //ExcelTemplate
xla.Save(workbook, Page.Response, "WorkbookWithMacros_out.xlsm", false); //ExcelApplication
wt.Save(Page.Response, "DocWithMacros_out.docm", false); //WordTemplate
wapp.Save(document, Page.Response, "DocWithMacros_out.doc", false); //WordApplication