308154

The most common reason of trouble with TANGO Interactive startup is wrong environment variables for UNIX or, for Windows,  installation of the plugin in a wrong directory. These errors make TI plugin invisible to Netscape or Internet Explorer browsers.

This section discusses troubleshooting for Netscape browser. Internet Explorer installations are usually less susceptible to problems.

The first thing to check is whether your plugin has been correcly installed. Go to Netscape's  Help/About Plug-ins window. You should see something like this:

TANGO Interactive [v. 2.0.7.0]

File name: F:\Program Files\Netscape\Communicator\Program\plugins\nptango.dll
Collaboratory system for the Web created by
WebWisdom.com 

Mime Type

Description

 Suffixes

 Enabled

application/x-collaboratory

TANGO Interactive

tng

Yes


 

If you do not see this entry, you haven't installed TANGO  Interactive plugin according to the instruction. Begin from restarting the browser. On some UNIX poltforms Netscape browser needs to be restarted twice to accept new plugin. If problem persists, please, check enviromental variables (UNIX only)  or repeat the installation process.

If your plug-in is correctly installed and you still experience problems, please, start Java console (use Netscape's "Communicator" menu). Then, start TANGO Interactive again. The messages appearing in the console should look similar to the following:

jconst_2startup

When the line: LocalBase: TANGO Interactive Plugin, 2.0.x.x appears in the Java console, you should have TI login window on your screen:

tango2SM_loginwindow

Type in your user ID and password and select the TI server from the menu. If TANGO Interactive client cannot connect to the selected server, it will pop-up an error message window and quit.This can be caused by the following problems:

  • the selected server is not running
  • you have network connectivity or performance problem
  • you are behind firewall.

If you are behind a firewall, you must have a proxy server installed somewhere on your network to be able to access Internet. TI 2 client provides support for firewalls, using SOCKS4 protocol. You must configure your browser to use proxy servers:

netscape_proxy_config

In the example above, the browser is configured to use proxy server running on the machine beast.npac.syr.edu. The setup uses default ports for proxy server (8080) and for the SOCKS server (1080). TI client is able to obtain proxy server settings from the browser prefs.js file. If you are behind the firewall, you MUST setup proxies for both HTTP and SOCKS protocol: the HTTP proxy is used to download TI client modules and data, and the SOCKS server enables communication with the TI server. The proxy servers for different protocols can run on different machines.

From experience, we know that firewall problem may be a difficult one. The setup described above is sometimes insufficient. Majority of the TI applets, including the Session Manager, communicate with the HTTP server from which they have been downloaded. We have seen firewalls incompatible with Java security model. Such firewalls will prevent TI (and, for that matter, any other applet) from getting information they need to operate. If you have such a firewall, you will see Java security exceptions with a message stating that applets loaded from the server, say,  www.abc.eduviolates security by trying to connect to the server www.abc.edu. This is a bug or misconfiguration of the firewall software, which will prevent you from running ANY Java applets that read data from the server. Contact the firewall vendor or your system administrator. (Note that many proxy servers, such as Netscape Proxy Server, handle such situations without any problem)

An occasional source of problems is Netscape's use of wrong classes cached in memory or on disk. If you get Java exceptions of any kind, flush browser's cache. Set cache size to 0 for both memory and disk caches if you experience problems. Once you are comfortable with the system, restore the cache size to useful values.

Yet another rare set of problems is related to the CLASSPATH variable. This problem usually affects Java developers' machines. Netscape always grabs Java classes from local disk before it gets them from the net. TANGO Interactive SM uses Swing widget libraries. Please, be aware that shall you have a different version of Swing classes in any directory specified in your CLASSPATH, Netscape is going to  find and load them and TI client  may crash.

If after reading this page you still have problems,  please,  and send us a message.

NOTA BENE: If you decide to contact us for support, you must attach contents of your Java console. We cannot diagnose problems without seeing it. Java console is started from the Communicator menu of your Netscape browser, or from the View menu of Internet Explorer.

Picture
WebWisdom Home