When attempting to convert an existing polyline to the Remote Area polyline, you get the following error when selecting a pline. Error: Automation Error. Key not found Command:

Area # section is blank or missing remote areas in the AutoCalc Setup dialog box. Area number is not recognized

Edit Remote Area dialog box is cut off (Can also happen to the main HydraCALC for Revit Setup dialog box)

Machine is set up to generate old-style (pre-AutoCAD 14) polylines. Flowing Heads Remote Area

Command Failure for External Command... Object reference not set to an instance of an object

Step 1a.1 - You may be missing a selected pipe type from master.dat or no pipe type has been selected for a particular system component

When attempting to setup a sprinkler head, after clicking OK in the definition window, the command prompt looks like this and no sprinkler head is inserted;

When selecting a pipe for the Move Main command, you get a fatal error

Generic Model template not found. Please select it.

Unable to select a pipe or fitting when trying to use the Delete Pipe tool.

No connectable heads found within distance specified for the line

illustrated, or heads were already connected ...

No connectable heads message comes up, even when there are obviously heads that can be connected. Can also be error stating Please re-select line away from other lines

Error placing Reference Points or Demand Area annotation... The 3D view ownerDBViewId is not locked.

When Opening HydraCAD or trying to list a drawing, you recieve any Error containing the following CLSID:

44D62FAE-67A7-4131-BF38-489CDFE44738

Or any of the following HRESULT error numbers:

0x800736B1

0x80040154

0x80070002

0x80080005

0x80029C4A TYPE_E_CANTLOADLIBRARY

One or more toolbars cannot be found after selecting a menu or command.

This happens because the toolbar is being opened 'off screen'. This usually happens when the computer has a dual monitor but the 2nd monitor isn't currently connected. 

Printing a calc shows this error in HydraVIEW;

File not found Runtime Error 53

When selecting Adjustable Ring Hangers for pipe sizes larger than 8" the detail does not show.

Run-time error 3051... The Microsoft Jet database engine cannot open the file

Can happen when opening HydraLIST or Head Selector

50.00.14+

Blacked out cells in Head Selector dialog

After opening AutoCAD and a drawing, you have a dead area where you can't draw nor does anything display.  Usually next to a compressed palette.  Note in the image below how the crosshairs do not extend to this area.