The first place it seems you are going wrong is not looking the command up in the manual (or if you have, understanding the parameters). Here is a like to
RESTORE DATABASE - IBM DB2 9.7 for Linux, UNIX, and Windows in the Information Center.
restore db visilog2 incremental taken at </data1/db2inst1/VISILOG2.0.db2inst1.NODE0000.CATN0000.201011100145 39.001> into test1
The parameter Taken At needs a timestamp after it. That is found as this 20101110014539 from the backup file name.
It is usually best to let DB2 know where this backup file is located. Since yours appears to be on disk, that would be the FROM parameter which needs a Device or Directory.
RESTORE DB VISILOG2 INCREMENTAL FROM /DATA/DB2INST1 TAKEN AT 20101110014539 INTO TEST1
PS, I am not sure how well this will work. It looks like you are restoring an Incremental copy of one database into another database. This is best done with a Full Backup and not an Incremental. Since I have never done this, I am assuming (if it will work), that it can find and has access to the Full Backup created before the Incremental Backup (since it will have to start the recovery process form that Full Backup).