in different net section wingate 5.22 problem

[ccuser]

Software information : Windows 2003 and wingate 5.22 . two network adapter, with 2 IP addresses ( internet network adapter 137.6.3.67 net mask 255.255.254.0. gateway 137.6.3.254 intranet network adapter 10.75.107.40 net mask 255.255.255.0 )
Clients is win xp or win 98
If net gateway of intranet(10.75.107.1) is blank, the server's net section can proxy , but another user (not server’net section, such as 10.75.14.*) can’t proxy. If net gateway of intranet(10.75.107.1) is writed, the server's net section cannot proxy , but another user (not server’ net section, such as 10.75.14.*) can proxy. Why ? wait impatiently for help.