Hey Rhonda,
It appears you are trying to set the lookup fields directly? Instead, you'll want to set the "reference" (foreign key) field in the relationship. Based on the word prepending the hyphen, in your case may be called Related Request? Once that field is set, the lookups should work as expected.
Put another way, you'll need to grab the Record ID# from the context of the button click, which would then be used to set a field on your child table, so something like:
// …
// Are you trying to set lookups?
// "&_fid_19=" & URLEncode ([Request - Name])
// "&_fid_20=" & URLEncode ([Request - Order Number])
// If so, instead set the Reference field
"&_fid_xyz=" & URLEncode ([Record ID#])Also, I'd suggest wrapping your value in the URLEncode() function.
Hopefully that helps!