Okay, while still being a tenderfoot at all this FMC stuff, I'm most likely doing something completely wrong, but here's my deal:


After reading the PMDG 737 FMC manual, I figured I would go ahead and load up a flight and see if I could actually program the darn thing.  I use the "flight planner" and plan a flight from Sacramento to San Diego, and note all the waypoints and airways that would be used. 

As needed by the FMC, I enter all the waypoints to the RTE pages, (e.g. Direct to LIM from KSMF, to AVE via J189, to DERBB via J7) etc.

Once I pass all the waypoint entry pages, and reach the SID selection page, I choose a SID that goes along with my taxi clearance from ATC to a runway.  However, once I choose a SID, then I get a message in the scratchpad reading:

DISCO inserted after LIAMM

Along with this, the first three waypoints on the now MOD RTE pages show "Route discontinuity" across them.


What am I doing wrong?

-HF

a rule of thumb is to enter the SID first, and then continue with the "normal " route.

FMC leaves a DISCO whenever you choose a SID transition.

Another reason is if the path has a too tight of a turn or too high airspeed.
HOWEVER, as in the real life it should be noted that "occasional DISCOs may occur in a departure or arrival procedure due to the methods used for coding the database" (Snippet from a real FMC manual)

Okay, I just tried to program the FMC again, but this time by choosing the departure SID before I entered the route.  However, once I choose a SID and activate it, I still get the same message saying:

DISCO inserted after LIAMM

Once I press clear, then it says:

DISCO inserted after LIAMM (1500) I believe.

Along with this, I cannot go enter my route, as now for the first page of waypoints, there's just a screen full of "Route Discontinuity" and hyphens.

Any help?

It's a conditional waypoint...or a pseudo waypoint if you like. It's not a fixed geographical location, but a "floating" one, which depends on aircraft state and condition.

If your SID calls for a tight turn for example, try enter a slower speed, maybe you will be able to make it.

Are you aware of the term conditional waypoints in the first place?