Error code 38 on entering cash shop

Umm... Not necessarily.

Every F is equal to 1111 in binary. The first bit is the Sign bit, the following bits are the Value. if this was simple 4 bit signed number, then F (1111) would be -7. 0111 would be 7.

Any HEX represented number with the first digit greater than 8 would be negative. (Assuming the first bit is the sign, which varies by system.)

0x00000001 = 1
0x80000001 = -1

But again, it can vary widely by processor system. Some systems use the first bit as 0 for negative and 1 for positive numbers, in which case

0x00000001 = -1
0x80000001 = 1

The numbers you are quoting look to be One's Complement versions. In which case an all F number would be 0. But it's silly to nitpick when you are only half right.

MS runs on windows, which has only ever run on processors using two's complement. 0xFFFFFFFF is either -1 or max int (32 bit, ~2b), depending on whether it's viewed as signed or unsigned.
Trying to argue that there are different systems and MS might be using one's complement or sign+magnitude, is as ridiculous as suggesting it might be using EBCDIC for text, or maybe CDC's 6-bit system (whose name I forget).

Anyway, this is irrelevant to the current bug, for reasons mentioned before.