I have a DNN 5.2.1 site that is currently getting the event log flooded with errors such as the one below. It appears to have something to do with either caching or localization. The site is Spanish language with a core language pack installed, to which some customisations have been made in the language editor. Can anyone suggest a solution, please?

AssemblyVersion: 5.2.1
PortalID: 0
PortalName: Staging
UserID: 8
UserName: paul
ActiveTabID: 54
ActiveTabName: Log Viewer
RawURL: /Admin/LogViewer.aspx
AbsoluteURL: /Default.aspx
AbsoluteURLReferrer: http://ivida.vidavia.net/Admin.aspx
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: 7945ebf0-38fc-4546-84a4-0b3e738244de
InnerException: Data at the root level is invalid. Line 1119, position 9.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Xml.XmlTextReaderImpl.Throw
StackTrace:
Message: System.Xml.XmlException: Data at the root level is invalid. Line 1119, position 9. at System.Xml.XmlTextReaderImpl.Throw(Exception e) at System.Xml.XmlTextReaderImpl.Throw(String res, String arg) at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace() at System.Xml.XmlTextReaderImpl.ParseDocumentContent() at System.Xml.XmlTextReaderImpl.Read() at System.Xml.XPath.XPathDocument.LoadFromReader(XmlReader reader, XmlSpace space) at System.Xml.XPath.XPathDocument..ctor(String uri, XmlSpace space) at System.Xml.XPath.XPathDocument..ctor(String uri) at DotNetNuke.Services.Localization.Localization.GetResourceFileCallBack(CacheItemArgs cacheItemArgs) at DotNetNuke.Common.Utilities.DataCache.GetCachedData[TObject](CacheItemArgs cacheItemArgs, CacheItemExpiredCallback cacheItemExpired)
Source:
Nombre del Servidor: STAGING-HT

Sometimes, you just have to ask the question to realise you already know the answer . After running the resource file checker tool in the languages page, I found the culprits (see below). The history of this site is 5.1.4 -> 5.2.1. I don't know if the files originated in one or other of the release packages or were damaged in the upgrade. There were similarly malformed files in the core Spanish language pack that I installed.