Is that your full formula? It does not appear there is anything beyond this line & "&_fid_30=" that would cause it to do anything. It would need to be similar to this line & "&rid=" & [Record ID#] where you put a field or piece of data there for it to take.
var text urlToExecute = URLRoot() & "db/" & Dbid() & "?a=API_EditRecord&apptoken=cnbri4sbttfxsfys53ftbiz34vv"
& "&rid=" & [Record ID#]
& "&_fid_30=" & "data"
& "&_fid_111=" & [or field]
If that was not the issue and you sanitized the formula, try posting it again with something in place of the removed parts.