["Berke, Richard" <Richard_Berke@xxxxxxxxxxxxxx>]

You get a parsing error if you attempt to enter a filter under the sequence:

Capture
  Start
     Filter  
       <enter your filter name and filter string>

You must first perform:

Edit
   Capture filters
      <enter the filter descriptive name>
      <enter the filter string contents/commands>
      New
      Save
   Close

THEN you go into 
 
Capture
   Start
     Filter

You'll see your filter there by name and you can select it.
Ethereal parses the stored filter, and places its name and string
in its fields.  You can then actually use the filter in your capture.

I don't know if this sequence is required in implementations on other
platforms.
Seems way too rigid/cumbersome, but I don't have the skill to offer changes
to the code.

Richard Berke
T. Rowe Price