Passing parameters to subreport - missing value error

I am trying to pass ID's to a subreport as they are listed in the main report. It works fine when I run it in the subreport and manually type in the ID into the parameter field but when I run it from the main report, it is giving me a "parameter is missing value" error.

Here is an example of my main report structure generated from an SQL query:

Table Structure:

Table Structure:
| Area |
| -------- |
| ID |
| -------- |
| SubReport|

Example report output:

*Report generates a list of IDs and is grouped/sorted by the Area

Area: Atlanta
 ID#1234
   -Call Subreport for ID#1234 profile
 ID#1235
    -Call Subreport for ID#1235 profile
Area: Boston
 ID#1236
   -Call Subreport for ID#1236 profile

Parameter Settings in main report + subreport: (settings are identical)

A. Parameter Settings

1. It is set to visually hidden
2. Declared as a text field
3. Available + default values (not specified)

B. DataSet Properties (Parameters)

1. Parameter Name :prm_ID
2. Parameter Value [@prm_ID]

Please let me know if I can provide any more information