is a white and black wire okay for dryer breakers or are you supposed to see two black or red wires attached to the breaker for the dryer?? or is there supposed to be three wires attached to the breaker??
do You have a picture ? what is the gauge of the wire ? what is the size of the breaker ?
Something like this:
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Only 2 attached to the breaker in a 240 volt single phase residential. The three plug will include 2 hot plus ground and 4 plug include 2 hot plus ground and neutral. Sometimes the hot’s are black (or both red and black)
(edit: see David’s picture) 
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Technically you should mark the white wire on the end either red or black to identify it as an ungrounded conductor (hot). This is usually done with electrical tape or permanent marker, I would not write it up for that if that is all that is wrong.
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The only time that a white insulated wire can be used as an ungrounded conductor is when it is within a cable assembly like NM cable, AC cable, or MC cable and it is re-identified as Bob mentioned. A white conductor in a raceway cannot be re-identified as an ungrounded conductor. It is normal to see a white conductor on a 2-pole circuit breaker in older homes because the re-identification rule has not always been in the NEC.
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A three wire connection is two hots and a neutral, not a ground. The grounding is accomplished by a jumper to neutral. If has been disallowed for many code cycles.
If NM cable was used the bare cannot be used as the neutral.
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Around here it is nearly always the AC breaker where the work was done by the HVAC contractor who didn’t care (or know) about re-identifying the white wire as a hot.
It depends on how old the house is…old houses had a two hots and a grounding conductor (white was used as a hot) and new houses have two hots (typically red and black), a neutral and a grounding conductor. Often the dryer cord is changed out at the appliance to match the outlet that already exists. Dryers are almost always 30 amp breakers.