An annoying feature of Project Server 2010 when it shipped was the inability to fully customise the risk list of a Project workspace. Whilst most of the list could be customised, when you tried to modify the Cost, Cost Exposure or Exposure columns, you would get a really annoying ‘An Unexpected error has occurred’ message, even cracking open SharePoint Designer to try and modify those columns would result in an error.
When you dig into the ULS logs, you see the following errors:
Unexpected System.FormatException: Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at Microsoft.SharePoint.SPGlobal.GetNamedIntItem(XmlNode node, String strName, Int32& iValue) at Microsoft.SharePoint.SPFieldCalculated.get_CurrencyLocaleId() at Microsoft.SharePoint.ApplicationPages.BasicFieldEditPage.get_CurrencyLocaleId() at Microsoft.SharePoint.ApplicationPages.BasicFieldEditPage.PopulateCurrencyList(DropDownList ddl) at Microsoft.SharePoint.ApplicationPages.BasicFieldEditPage.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
Thanks to a heads up from Brian Smith, this issue has been addressed in Hotfix 2459113 which is part of the Project Server 2010 December CU, so get patching.