Hi Kiran,
Just wanted to check whether the sick leave is applicable for the same rule group where the other leave type where the error message is getting displayed if the quota is more than 50. This works based upon the settings in the tabel V_PTARQ_TPROCESS where you must have checked the check box Check Includes Unposted Requests.
In case if the sick leave and other leave belongs to same rule group then the other check is in table V_T556A where negative deduction is there for the quota.
Regards,
Mithun K