Objecttive-C各种问题

1.invalid argument type 'void' to unary expression

 @try{
         if (![mJQFMDB open]) {
             NSLog(@"Could not open db.");
             return NO;
         }else {
             NSArray *mLineInfoAry = responseObject[@"Data"];
             if(mLineInfoAry != nil && mLineInfoAry.count > ) {
                 for (NSDictionary *lineInfo in mLineInfoAry) {

                 }
             }
             return YES;
         }
     }@catch(NSException *ex) {
         [TExUtils uploadEx:ex];
     }@finally {
         [mFMDB close];
     }

该类继承父类，父类成员变量如下：

 @interface BasicDataBase : NSObject {
     //成员变量
     @public
     FMDatabase *mFMDB;
     @public
     JQFMDB *mJQFMDB;
 }