Extra line of input was entered into the VPUMP.DAT file found here; \HES\HydraCAD\Ver50\Programs\3DFTGS Unhandled Exception Insert Pump n/a

No error, pump just doesn't insert 

Revit could not complete the external command... Name contains illegal characters

Discharge and or Suction inputs were typed in and not entered via the pull down. input new pump

Pump is in water supply but no reference point PI

Command Failure for External Command... ...System.IO.DirectoryNotFoundException

Revit could not complete the external command.... Details: Name must be unique... At HCAD_Revit_Tools.CAD3.Insert_Pump.Go

Runtime Error 62: Input past end of file

After running an update to 50.54, user is getting this error when trying to add a fitting by right-clicking the fittings cell, a dialog box pops up saying,  May happen with Pipe Schedule and adding a Pump as well.

File to load paths and Dirs.(AND STRING CONVERSION)
CommandLine... yadda yadda yadda

No Ribbons / only the HydraCAD Ribbon appears, and no commands work.
Revit could not complete the external command. Could not load file or assembly. The system cannot find the specified file. 

When starting the AutoCALC process, you get this error;

Could not find fitting match for Pump Only/Test Point Please check!!

You also see an Accessing Database window with a partial green progress bar.

No Operating Heads of Flows Found!!  Please check...

During the install of HydraCAD, you get an error, "Setup Needs the Next Disk, Please insert disk 1 that contains the file data2cab"

Inserting a pipe dimension (pipex) places it at the end of the pipe, including its center grip or not even on the pipe at all

See solution #3 if the PIPEX is not on the pipe

Error when attempting to make a fluid delivery time file...

Calc process gets stuck on step 5a.3b
This is caused bad pump routing.

There was an error while inserting the specified element.... The given path's format is not supported

When trying to insert a Sprinkler Head Schedule (SHS command), after viewing the setup dialog box, then selecting sprinkler heads, when asked to select a location for the guide, you get the error;

Please pick start point for schedule

Error: bad argument value: non-negative: -1

Calc stops at Step 2.3 (Can also show Run-time error 62)

System flow demand exceeds the maximum rated flow...

Command failure for external command ... System.IO.FileNotFoundException ... File name 'AWSSDK'