Oracle Database Discussions

I would appreciate some pointers on this if possible, as I'm a bit of an rman novice.
Our rman backup logs indicated a failure and in the directory where it puts its files there appeared a large number of files for the 18th, which was the date of the failure. Previous days backups generated 5 files of moderate size. When it failed it generated between 30 - 40 G of files ( it looks like one for each database file ).
The full backup is early monday morning, and the rest incremental :

I have placed the rman log, the script and a the full directory file listing here : http://www.tinshed.plus.com/rman/

Thanks in advance - George

-rw-r----- 1 oracle dba 1073750016 Jan 18 00:03 database_f734055071_s244_s1
-rw-r----- 1 oracle dba 1073750016 Jan 18 00:03 database_f734055096_s245_s1
-rw-r----- 1 oracle dba 1073750016 Jan 18 00:03 database_f734573008_s281_s1
-rw-r----- 1 oracle dba 1073750016 Jan 18 00:03 database_f734055045_s243_s1
-rw-r----- 1 oracle dba 524296192 Jan 18 00:03 database_f734055121_s246_s1
-rw-r----- 1 oracle dba 1073750016 Jan 18 00:03 database_f734055020_s242_s1
-rw-r----- 1 oracle dba 4294975488 Jan 18 00:02 database_f734054454_s233_s1
-rw-r----- 1 oracle dba 4294975488 Jan 18 00:02 database_f734054519_s234_s1
-rw-r----- 1 oracle dba 4294975488 Jan 18 00:02 database_f734054595_s235_s1
-rw-r----- 1 oracle dba 4294975488 Jan 18 00:02 database_f734054660_s236_s1
-rw-r----- 1 oracle dba 4294975488 Jan 18 00:02 database_f734054725_s237_s1
-rw-r----- 1 oracle dba 4294975488 Jan 18 00:02 database_f734054790_s238_s1
-rw-r----- 1 oracle dba 209723392 Jan 18 00:02 database_f734055136_s247_s1
-rw-r----- 1 oracle dba 73408512 Jan 18 00:02 database_f734055143_s248_s1
-rw-r----- 1 oracle dba 67117056 Jan 18 00:02 database_f734055146_s249_s1
-rw-r----- 1 oracle dba 4194312192 Jan 18 00:02 database_f734054855_s239_s1
-rw-r----- 1 oracle dba 2147491840 Jan 18 00:02 database_f734054975_s241_s1
-rw-r----- 1 oracle dba 3221233664 Jan 18 00:02 database_f734054920_s240_s1
drwxr-xr-x 2 oracle dba 4096 Jan 18 00:00 logs
-rw-r----- 1 oracle dba 18710528 Jan 17 00:15 controlfile_c-1911789030-20110117-00
-rw-r----- 1 oracle dba 1343488 Jan 17 00:15 database_f740621746_s624_s1
-rw-r----- 1 oracle dba 2958848 Jan 17 00:15 database_f740621745_s623_s1
-rw-r----- 1 oracle dba 6415990784 Jan 17 00:15 database_f740620829_s622_s1
-rw-r----- 1 oracle dba 172391424 Jan 17 00:00 database_f740620814_s621_s1