error storing modern office files (xlsx, docx, pptx) in database - vb.net

Question

I'm building a system that allows adding attachments. I have almost everything working, but any of the "open" formats from newer office files are coming out with the following error:
"We found a problem with some of the content in file.xlsx. Do you want us to recover as much as we can? IF you trust the source of this workbook, click yes."
clicking yes, usually will open the file, but I'd like to get past this entirely.
Files are stored in SQL Server, and uploaded and retrieved by stored procedure.
uploadFunction:
Protected Sub btnUploadAttachment_Click(sender As Object, e As EventArgs) Handles btnUploadAttachment.Click
Try
Dim fileCount As Integer = 0
For Each file As UploadedFile In filFileAttachment.UploadedFiles
fileCount += 1
Using conn As New SqlConnection With {.ConnectionString = SadSql},
cmd As New SqlCommand With {.CommandText = "RAD_ProjectTracker.dbo.spProject_Attachment_Add", .Connection = conn, .CommandType = CommandType.StoredProcedure, .CommandTimeout = SQLCommandTimeout}
Dim buffer As Byte()
Using s As Stream = file.InputStream
buffer = New Byte(s.Length) {}
s.Read(buffer, 0, buffer.Length)
End Using
cmd.Parameters.Add("#PROJECT_ID", SqlDbType.Int).Value = hfProjectID.Value
cmd.Parameters.Add("#VERSION_ID", SqlDbType.Int).Value = hfVersionID.Value
If Not hfJobID.Value.IsNullOrEmpty() Then cmd.Parameters.Add("#JOB_ID", SqlDbType.Int).Value = hfJobID.Value
cmd.Parameters.Add("#USER_ID", SqlDbType.Int).Value = Session("uid")
cmd.Parameters.Add("#ATTACHMENT", SqlDbType.VarBinary).Value = buffer
cmd.Parameters.Add("#ATTACHMENT_TYPE", SqlDbType.VarChar).Value = "ATTACH_TYPE_DOCUMENT"
cmd.Parameters.Add("#MIME_TYPE", SqlDbType.VarChar).Value = file.ContentType
cmd.Parameters.Add("#FILE_NAME", SqlDbType.VarChar).Value = file.FileName
If Not txtDescription.Text.IsNullOrEmpty() Then cmd.Parameters.Add("#DESCRIPTION", SqlDbType.VarChar).Value = txtDescription.Text
conn.Open()
cmd.ExecuteNonQuery()
conn.Close()
End Using
Next
ReturnToAttachments()
Catch ex As Exception
Dim s As String = ex.Message
End Try
End Sub
and the retrieval code:
Dim tsql As String = "Exec RAD_ProjectTracker.dbo.spProject_Attachments_Get #ATTACHMENT_ID=" & dataItem("ATTACHMENT_ID").Text
Dim dt As DataTable = GetSQLDataSet(tsql, True).TablesSafe(0)
If dt.Rows.Count > 0 Then
Dim dr As DataRow = dt.RowsSafe(0)
Dim file As Byte() = CType(dr("ATTACHMENT"), Byte())
Dim fileName As String = If(IsDBNull(dr("FILE_NAME")), "attachment", CStr(dr("FILE_NAME")))
Response.Clear()
Response.ClearHeaders()
Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName)
Response.ClearContent()
Response.ContentType = dr("MIME_TYPE")
Response.BinaryWrite(file)
Response.End()
End If
I've tested .xls, .dox, .ppt, .png, .jpg, .txt, and a few others and they all work fine.
It's only the .xlsx, .docx, and .pptx that seem to be having issues.
I've googled around and haven't been able to find much. Is there an extra step to these documents? or perhaps i am doing something in the wrong order?
Any help would be appreciated.