Revit could not complete the external command     System.NullReferenceException

ERROR: No fittings were found on the selected pipe

Command Failure for External Command... System.NullReferenceException

Printing a calc shows this error in HydraVIEW;

File not found Runtime Error 53

After printing your data in HydraLIST, when HydraVIEW opens you attempt to change the default printer. 

You get an error "Page Setup - Unknown filetype found 'HLTF'"

After clicking the Start AutoCALCs (SAL command) button but BEFORE the AutoCALC Setup window, you get the error; 

Unhandled exception has occurred in a component in your application. If you click Continue, the application will ignore this error and attempt to continue.

The input string '1◆' was not in a correct format.

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

 Line / Main tags are blocking items behind the text / tags are not transparent

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

When opening HydraCAD, you get this error

Unhandled Exception...DAO32Server...

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

Keyboard alias "SAC"

After clicking OK in the AutoCalc Setup window and just before the process begins, you get the following error messages;

Problem updating your Hcad_env.ini file.  /n Will try to rebuild file. /r Pick OK then Restart AutoCALC

Your Hcad_env.ini file is possibly corrupted.  This calc will not continue

After running an Autolist, in HydraLIST and the LINES tab you have a listing tag ID called RM

No error occurs but HydraCAD will not properly load and Hcad commands do not work.  

A quick test is to select the drop menu [File|New], select the template file 'HydraCAD Imperial Default.dwt'.  

The Drawing Setup window should appear but it does not, it loads straight into a blank drawing.

This is what you should see (press F2 to review the text window);

Instead you only see;

HCAD_ADS r4 functions Loaded.

AutoCAD menu utilities loaded.
Requires an integer between 0 and 32767.

3dFitting registry keys found

Requires an integer between 0 and 32767. 
 

When attempting to create a new FSC definition, you get this error message.  Clicking OK closes the command

Drawing Setup dialog doesn't load

No error but when the HydraCAD template is selected, it goes straight to the drawing and command prompt, it doesn't ask for the user to set the scale factor

Unhandled Exception... System.ArgumentOutOfRangeException: Index was out of range

When inserting a flexible sprinkler connection (FSC) after its setup, you get two error messages

Error importing hose over size percent, check your FSC dialog properties

Setting Over Percent to 10%

Error importing hose under size percent, check your FSC dialog properties

Setting Under Percent to 20%

Clicking OK in each window will allow you to continue and insert the FSC detail

When defining a flexible sprinkler connection, the following error is raised ("Input string was not in a correct format"):

No error reported for FSC even when maximum length is clearly exceeded

If you view the FSC properties, it's possible the HoseLength and MaxNumberOfBends values are not set.