This happens to me. I know I'm not the OP, but here are my answers.

Platform: Windows 7
ISP: Cox
Type: CATV
Connection Speed: 3Mb/s
Date/Time: Ongoing since I received skill over 2 months ago. I could do it now if I were logged in.
Frequency: Always
Character Name: Blaise Lallaise
Race: Lalafell M
World: Istory
Class/Skill Rank: Between 20 and current rank of 24
Physical Level: Unknown, most likely 30+
Area/Coordinates: Anywhere, but mostly Ul'dah and Aetheryte camps in Thanalan.
Party or Solo: Solo
NPC Name: None
Monster Name: None
Details: I activate my macro to switch to lancer, in which I have this command: /eaction 2 "Pierce"
That /eaction fails, but my /eaction for Speed Surge in same macro succeeds. I receive no error message. Attempting to switch the slot number does not change the outcome.