Try

=COUNTIFS(INDIRECT("'"&A5&"'!$A$2:$A$298"),$F$1,
INDIRECT("'"&A5&"'!$E$2:$E$298"),$A21,
INDIRECT("'"&A5&"'!$G$2:$G$298"),$C21,
INDIRECT("'"&A5&"'!$H$2:$H$298"),$B21,
INDIRECT("'"&A5&"'!$L$2:$L$298"),F$3)