In the initial scene prior to the initial show titles when Donna sends Joe a fax, the fax starts printing before the fax modem handshake is complete. This is a technological impossibility as no data is transmitted until the handshake is successful.
In the opening scene Donna turns on her computer and the bios reports the CPU as a 286 with 64MB of ram. The 286 is only capable of addressing a maximum of 16MB.
In the opening scene Donna turns on her computer and it boots into DOS then loads Windows 3. When loading DOS, the words "Starting MS-DOS..." appears, which is consistent with the loading of DOS 6 and above. This episode is based in 1990, and DOS 6 didn't come out until 1993.