INT 2F - License Service API - GET ERROR
        AX = 7004h
        CX = license server index (0000h to 001Fh)
        DS:DX -> SLSGETERROR structure (see below)
        ES:BX = provider specific handle for the license context
Return: AL = status
            00h not installed
            FFh installed
SeeAlso: AX=7000h,AX=7001h

Format of SLSGETERROR structure:
Offset  Size    Description
 00h    DWORD   (return) status code
 04h    DWORD   handle identifying license context
 08h    DWORD   error code
 0Ch    DWORD   buffer size in bytes
 10h  N BYTEs   data buffer

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