Many hosting companies, like mine, won’t have the AJAX Extensions installed in the GAC for quite a while, if ever. No worries, you can just put the DLLs in your Bin folder. Since MS hasn’t graced us with the DLLs, so you’ll have to get them out of your GAC. I haven’t found a way to copy DLLs using Windows Explorer, but command-line never fails.
copy “C:WINDOWSassemblyGAC_MSILSystem.Web.Extensions1.0.61025.0__31bf3856ad364e35” C:devMyAppBin
copy “C:WINDOWSassemblyGAC_MSILSystem.Web.Extensions.Design1.0.61025.0__31bf3856ad364e35” C:devMyAppBin