Reverted back to v5.x, resulting in: Parse error: syntax error, unexpected T_OBJECT_OPERATOR

Had attempted to upgrade to 6.x, went awry. Attempted to avert back to version 5.x
Worked for bit then, ..........

Parse error: syntax error, unexpected T_OBJECT_OPERATOR in /home/lovebop0/public_html/d/sites/all/modules/aggregation/aggregation.module on line 193

I'm guessing that I need to fix this error before I can resume my upgrade attempt.

Any idea how I fix this?

Thanks