The prompt to " Specify point to insert the block:" accepts a picked point or a number. The picked point is provided by the user. If the user wants to do a number or string found in the POINT attribute of the POINT block, the user can enter that value at the prompt. However, the value to search must not contain a space as this code makes no effort for that type of data.
You will need to verify the DEH block is either inserted into the drawing or is available to be found within the Support Files Search Path as listed in the Files tab of the Options dialog.