Your wipers have siezed you have to take them apart.
The shaft where the wiper goes through which connects to the wiper arm has seized. Because after a while when it rains the water gets throught to the shaft and pits the metal causing it to corrode.
Taking them out is easy but takes some time because you hace to take the hole linkage out to take it apart.
First take off any covers that are in the way including air filter cover.
Then there are 3 screws which hold the bulk cover on one at each end and 1 in the middle.
There are 3 bolts that hold the Linkage in place 1 at each end and 1 ind the middle.
Once these bolts are out you have to slide the linkage out (to the left).
Once out you will see what needs to be done, The best way to get the wiper shaft out is to put the nut back on it and hit it with a rubber hammer not to hard or you will crack the housing which is only cast iron. Once seperated clean up the shafts with wet and dry paper then grease them up and put it all back together.
Should work fine after that I know this as I work as a Taxi driver At Gatwick Airport where we have ove Forty of these cars and it has happened to at least 75%.
Good luck.
Don Barnes, September 2005