What causes a file not found dll error?

[colepink]

Could anyone tell me please, in plain English, what this error message means and why, after weeks of working correctly, it happened once yesterday. A button on a web site calls a web service when clicked and this happened. I have read up on the error and the answers involve using something to do serialisation of some type. I have no real idea what this means. I've always just written sites and published them to a server. Never had to serialise anything myself ...?\[code\]Could not find file 'C:\Temp\x3amdh5p.dll'.at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPathat System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath) at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share) at Microsoft.CSharp.CSharpCodeGenerator.FromFileBatch(CompilerParameters options, String[] fileNames) at Microsoft.CSharp.CSharpCodeGenerator.FromSourceBatch(CompilerParameters options, String[] sources) at Microsoft.CSharp.CSharpCodeGenerator.System.CodeDom.Compiler.ICodeCompiler.CompileAssemblyFromSourceBatch(CompilerParameters options, String[] sources)at System.CodeDom.Compiler.CodeDomProvider.CompileAssemblyFromSource(CompilerParameters options, String[] sources)at System.Xml.Serialization.Compiler.Compile(Assembly parent, String ns, XmlSerializerCompilerParameters xmlParameters, Evidence evidence)at System.Xml.Serialization.TempAssembly.GenerateAssembly(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, Evidence evidence, XmlSerializerCompilerParameters parameters, Assembly assembly, Hashtable assemblies)at System.Xml.Serialization.XmlSerializer.GetSerializersFromCache(XmlMapping[] mappings, Type type)at System.Xml.Serialization.XmlSerializer.FromMappings(XmlMapping[] mappings, Type type)at System.Web.Services.Protocols.SoapClientType..ctor(Type type)at System.Web.Services.Protocols.SoapHttpClientProtocol..ctor()at GWebService.Service1..ctor()\[/code\]