Windows

hi
i have installed w2k terminal server for 2 users. these 2 users are from remote locations and connect via dial up. The problem is that. 2 of them can always connect and work fine but sometimes can't print. (the printers are connected their computers. and i use net use command to map their lpt ports.) (the program make me map the lpt ports). the times when these 2 remote computers can't print i ping the server but can't find and also can't map the printers.
for example: net use lpt1: \\10.10.1.10\ibm1
when i use this command it gives me the error code of that, 53 the network path was not found.
sometimes i shutdown the server and restart it and this solve the problem but sometimes i restart the server for 5 times but nothing is changed.
how can i solve this problem.
i frequently see this problem
thanks in advance.