problem with uploading models and renderings

i cannot upload model. i choose cad file to upload it show type of it and than line disappeare it means that file is not uploading and i see message "there is an error please try again later" please tell me what is something wrong or it should be like that. i cannot upload new renderings for other people's models. i press the model than press "rendering" there should be field "chose file",but there is no field.instead of that i see button "add your files".
4 Answers

Neither my upload is not working, my problem is described here
http://grabcad.com/questions/upload-dont-work