If the regional setting for decimal is "," instead of "." you have 2 options:1. Change the regional settings for decimal symbol to "."2. Modify the font size values in the report stylesheet to not include any decimal values. To do this:- Browse to <ArcGIS Install Dir>\Desktop10.0\Styles\ReportWriter\ and open the Styles.xml in Notepad or another xml editor- Search for "." in the document- Anywhere it says Font Size = and the value has a decimal round the value up or down to the nearest whole digit. So 20.25 becomes 20.- Save the xmlIf the regional setting for decimal symbol is already "." then it is likely that a font is not installed on the machine that is being referenced in the Styles.xml. There are 2 options to resolve this:1. Install the font that the Stylesheet is requesting2. Modify the stylesheet to only use fonts that are installed on the machine-Browse to <ArcGIS Install Dir>\Desktop10.0\Styles\ReportWriter\ and open the Styles.xml in Notepad or another xml editor- Search for the font in the document- Replace the font with a font that is installed on the machine, for example replace Lucida Sans with Book Antiqua- Save the xmlTo determine which font is the issue, you will need .rlf (report layout file).- Open ArcMap and load the .rlf using View > Report > Load Report- In the Report Designer click the Styles Manager- This will produce an error, click to expand the details- In the first line under ***Exception Text*** there will be a statement like, System.ArgumentException: Font 'Lucida Sans' does not support style 'Regular'- This will indicate what font is unavailable and the font you will need to either load on the machine or remove from the stylesheet