the reason you get that is casue, windows XP (nt) will only allow print programes to use your parallel port,
Download This Software and they do this, in the left hand box type 0x378-0x378 then click add, then start, then update, if you get the error userport.sys not found, the copy the userport.sys file to your C:/windows/system32/drivers directory, then try running the LCD driver software.
tell me how it turns out. and how did you wire an LCD to your parallel port?