Hi Ian,
You might not be doing anything wrong!
If needed visit this page here on FF:
Frog Forum - Basic Frog First Aid
There was a thread recently (you could search for ) about an online vet, if needed?
In the meantime--If he is new to you and his enclosure. Aside from providing food ( Cal and Vit) , clean dechlorinated water (daily -if possible without disturbing him) ,proper temp/humidity ; you should cover three sides of the enclosure, and leave him be. Handling should be only if absolutely necessary ! ( ie I have frogs for over 2 years I have NEVER touched ). Provide complete darkness each night, with a consistent day/night cycle. Keep things calm and quite away form constant foot traffic around the enclosure.
Experts here on FF will need much more specific information:
-where did he come form
-how long have you had him
-photos of the enclosure if possible
-what kind of frog is he
-is he eating
-what is he eating
-when did he eat last
-is he pooping
-specific gauge information --temp and humidity
Hang in there. I hope this helps ?
Lynn