While most error messages are reasonably straightforward and self-explanatory, there are just a few cases where a satisfactory explanation warrants more space than the error tooltip in the Editor allows, and which you probably only need to read once or twice before you will then know what the concise message means. These longer explanations are provided selectively and are listed below – they are accessed directly from the error tooltip in the software via a help button 
, which is is only provided when such a longer explanation exists.
Interactive error: invalid number of arguments
STEM recognises the use of commas to format large numbers (e.g., 1,000,000) within expressions. So, whenever you use commas to separate elements within a formula such as if(Input1, 1, 0) you must always follow each comma with a space. If you omit the space, STEM may treat two adjacent numbers as one.
Data error 2056: Template replicates "Element 1", but not "Element 2"
The basic issue with replication is that, if you replicate something, you must also replicate anything else which directly refers to it. This is best illustrated by example:
- You can replicate a service, without replicating a precedent market segment, because there is no problem having multiple services driven from the same market.
- If you replicate a market segment, then you must replicate its dependent services too; otherwise they will not know which of the replicated market segments to refer to.
- If a resource is replicated, then a transformation with that resource as an input must be replicated too (one-many relationship).
- However, a replicated transformation (or service) can drive a non-replicated resource (many-one relationship).
If you need to calculate an overall total from various replicated services or resources, then the usual approach is to have a replicated transformation with a requirement (green line) for a non-replicated resource, which can act as an aggregator, as per (4) above.
As a general tip, anything you can do with manual copy and paste will work for replication. The cases which won’t replicate are the ones which leave a broken link with manual copy and paste.
Note: certain actions in the Editor can lead to a ‘ghost error’ where this replication problem is falsely reported. This can be cleared by closing and then re-opening your model. This triggers the necessary data-cleansing algorithm which, unfortunately, cannot be attempted once the associated user interfaces – dialogs and icons – have been initialised. (It is not necessary to exit the Editor.)