Not the bitmaps, the size its talking about is your sliders range.
Its either the MIN, MAX, or VAR values that are bad.

"min" MUST be zero or higher. Negatives not allowed.
"max" MUST be higher than "min"
"var" MUST be between, or equal to, either "min" or "max"

"There is no fate but what WE make." - CEO Cyberdyne Systems Corp.
A8.30.5 Commercial