In fact a kernel bug and not a bug in the udftools package.

Seems to be (partially) fixed in jaunty.
I say partially, because when udftools is restarted, the kernel still complains:

[  978.277135] ------------[ cut here ]------------                                     
[  978.277139] WARNING: at /home/kernel-ppa/mainline/build/fs/sysfs/dir.c:462 sysfs_add_one+0x49/0x50()                                                                         
[  978.277144] Hardware name: System Name                                               
[  978.277146] sysfs: duplicate filename 'pktcdvd0' can not be created                  
[  978.277149] Modules linked in: binfmt_misc bridge stp bnep radeon drm vboxnetflt vboxdrv video output ipt_REJECT ipt_LOG xt_recent xt_limit xt_tcpudp xt_state ipt_addrtype ip6table_filter ip6_tables nf_nat_irc nf_conntrack_irc nf_nat_ftp nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack_ftp nf_conntrack iptable_filter ip_tables x_tables dm_crypt psmouse lp rsrc_nonstatic pcmcia_core snd_cmipci gameport snd_pcm_oss snd_mixer_oss snd_pcm snd_page_alloc snd_opl3_lib snd_hwdep snd_mpu401_uart i2c_viapro snd_seq_dummy snd_seq_oss via_ircc ppdev snd_seq_midi pcspkr snd_rawmidi snd_seq_midi_event irda snd_seq crc_ccitt usblp snd_timer snd_seq_device parport_pc via_agp snd parport shpchp agpgart soundcore 8139too usbhid 8139cp mii aic7xxx scsi_transport_spi raid10 raid456 async_xor async_memcpy async_tx xor raid1 raid0 usb_storage multipath linear                       
[  978.277230] Pid: 5878, comm: pktsetup Not tainted 2.6.29-02062901-generic #02062901  
[  978.277233] Call Trace:                                                              
[  978.277246]  [<c013a736>] warn_slowpath+0x86/0xa0                                    
[  978.277256]  [<c02c1200>] ? sub_alloc+0x0/0x150                                      
[  978.277260]  [<c02c1261>] ? sub_alloc+0x61/0x150                                     
[  978.277266]  [<c02c13f0>] ? idr_get_empty_slot+0xa0/0x140                            
[  978.277270]  [<c02c150b>] ? ida_get_new_above+0x7b/0x180                             
[  978.277276]  [<c01d0bed>] ? find_inode+0x3d/0x70                                     
[  978.277280]  [<c020bc00>] ? sysfs_ilookup_test+0x0/0x20                              
[  978.277284]  [<c020bf21>] ? sysfs_find_dirent+0x21/0x30                              
[  978.277288]  [<c020bf4d>] ? __sysfs_add_one+0x1d/0x90                                
[  978.277292]  [<c01d22b9>] ? ilookup5+0x39/0x50                                       
[  978.277296]  [<c020c009>] sysfs_add_one+0x49/0x50                                    
[  978.277300]  [<c020c929>] create_dir+0x49/0x90                                       
[  978.277304]  [<c020c99b>] sysfs_create_dir+0x2b/0x50                                 
[  978.277310]  [<c02c1eee>] create_dir+0x1e/0x50                                       
[  978.277314]  [<c02c2296>] kobject_add_internal+0x86/0x100
[  978.277318]  [<c02c243c>] kobject_add_varg+0x4c/0x50
[  978.277324]  [<c02c674a>] ? string+0x2a/0xa0
[  978.277327]  [<c02c250f>] kobject_add+0x2f/0x60
[  978.277334]  [<c034ad33>] device_add+0x93/0x280
[  978.277338]  [<c034af32>] device_register+0x12/0x20
[  978.277342]  [<c034b215>] device_create_vargs+0x85/0xb0
[  978.277347]  [<c034b26b>] device_create+0x2b/0x30
[  978.277352]  [<c0357fe2>] pkt_sysfs_dev_new+0x42/0xb0
[  978.277357]  [<c03592ef>] pkt_setup_dev+0x1bf/0x220
[  978.277361]  [<c035941e>] pkt_ctl_ioctl+0xce/0x120
[  978.277368]  [<c01cb7dc>] vfs_ioctl+0x6c/0x80
[  978.277376]  [<c0185801>] ? set_marker+0x41/0x1d0
[  978.277381]  [<c01cc05a>] do_vfs_ioctl+0x6a/0x1b0
[  978.277385]  [<c01cc1f3>] sys_ioctl+0x53/0x70
[  978.277390]  [<c010346b>] sysenter_do_call+0x12/0x2f
[  978.277395]  [<c0185801>] ? set_marker+0x41/0x1d0
[  978.277398] ---[ end trace aec2168d659bce27 ]---
[  978.277404] kobject_add_internal failed for pktcdvd0 with -EEXIST, don't try to register things with the same name in the same directory.
[  978.277413] Pid: 5878, comm: pktsetup Tainted: G        W  2.6.29-02062901-generic #02062901
[  978.277416] Call Trace:
[  978.277421]  [<c02c22df>] kobject_add_internal+0xcf/0x100
[  978.277425]  [<c02c243c>] kobject_add_varg+0x4c/0x50
[  978.277429]  [<c02c674a>] ? string+0x2a/0xa0
[  978.277432]  [<c02c250f>] kobject_add+0x2f/0x60
[  978.277436]  [<c034ad33>] device_add+0x93/0x280
[  978.277440]  [<c034af32>] device_register+0x12/0x20
[  978.277444]  [<c034b215>] device_create_vargs+0x85/0xb0
[  978.277448]  [<c034b26b>] device_create+0x2b/0x30
[  978.277452]  [<c0357fe2>] pkt_sysfs_dev_new+0x42/0xb0
[  978.277456]  [<c03592ef>] pkt_setup_dev+0x1bf/0x220
[  978.277461]  [<c035941e>] pkt_ctl_ioctl+0xce/0x120
[  978.277465]  [<c01cb7dc>] vfs_ioctl+0x6c/0x80
[  978.277469]  [<c0185801>] ? set_marker+0x41/0x1d0
[  978.277473]  [<c01cc05a>] do_vfs_ioctl+0x6a/0x1b0
[  978.277477]  [<c01cc1f3>] sys_ioctl+0x53/0x70
[  978.277481]  [<c010346b>] sysenter_do_call+0x12/0x2f
[  978.277486]  [<c0185801>] ? set_marker+0x41/0x1d0

However, the crazy interaction with the input devices seems to be over.

Should I report the remaining issues as a new bug?