Premiere CS4 - AVCHD - Codec missing or unavailable

Question

Recently received captured footage from a Panasonic HDV camcorder captured onto a Mac. I am using Production Premium with Premiere Pro CS4. When I attempt to import the .mov files, they are black screen with no audio either.
I did a quick search on the net to see if CS4 supports AVCHD files and apparently it does. Seemingly also since it lists them as an available format when creating the project intially.
When I attempt to import the files, I get the "Codec missing or unavailable" error. I also receive an error when I try to open the file to view it in QuickTime. I have the latest version of QuickTime and am running on a Vista 64 bit system currently.
If CS4 lists the AVCHD format, should it also not support the files?
Do I have to convert the files in some way?
Is there a specific codec that may have not been installed when I installed the studio?
Since the program itself is up to date, is there another codec from Adobe that is required?
Thanks in advance for any assistance...
Don

Answer 1

Thanks for all the help thus far.
I did install GSpot and tested a video sample from the captured file. The Codec was listed as "hdv4" and the Video as "<unknown>". It's 1280 X720 and identified as .MOV/QT.
Listing the CODECs and other FILTERS gives me a list of "File Missing" items which all reference MainConcept(Adobe2) ... included below.
We did (years ago) purchase Main Concepts product for video. I thought that became redundant once Adobe started including their decoders within the their products. That is why I initially believed that there was a problem with the installation of the Adobe Production Premium product.
Do I need to upgrade or re-purchase the MainConcept product for this?
Does this seem like a reinstall issue for Production Studio CS4?
Recently, I am finding that I am ending up with more Mac based camcorder captures for editing. A lot of times these people have a consumer or low-end prosumer camcorder and a Mac laptop or whatnot and consider themselves "videographers". These people do not know how to capture in any other format than to  "plug it in and capture" and many times don't have any idea about CODECs  and formats. Many times, its the AVCHD format that has issues. I can either spend the money on a card (or whatever) reader and and attempt to capture it myself, or get my system updated to corrrectly read these (which I would prefer).
I've used Mac systems since the first one came out in 1984 and stopped using them when work dictated a PC format and Premiere (Macs really were not Movie producing until they bought Final Cut from Macromedia anyhow, ... they were Printing and graphic based systems before that). I'm "fully fluent" in most all things Mac because we have a couple of recent Mac with OSX at the office for graphics (no Final Cut Pro), I just dont have home access to a Mac at this time.
As far as the type of camcorder and format ... I was told it was a Panasonic .. I just (like always) received the captured footage ... from someone with a Mac.
DSH    FmtTag: 0x00ff        "MainConcept (Adobe2) AAC Decoder"    {214CD0D1-FC06-41B1-8BB8-84DA4CFB17D9}    0x00600000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2daac.ax"
DSH    Video    "MainConcept (Adobe2) H.264/AVC Decoder"    {FF890B41-A4C5-4B19-87CF-65D86EC12F1C}    0x00600000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2dsh264.ax"
DSH    MPEG1Packet    "MainConcept (Adobe2) MPEG Audio Decoder"    {25AD5730-4DE0-4CF8-952A-2AEF53AC4321}    0x005fffff    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2mcdsmpeg.ax"
DSH    MPEG1Packet    "MainConcept (Adobe2) MPEG Video Decoder"    {25AD5740-4DE0-4CF8-952A-2AEF53AC4321}    0x005fffff    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2mcdsmpeg.ax"
DSH    MPEG1Packet    "MainConcept (Adobe2) MPEG Video Decoder"    {25AD5740-4DE0-4CF8-952A-2AEF53AC4321}    0x005fffff    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2mcdsmpeg.ax"
DSH    MPEG1Packet    "MainConcept (Adobe2) MPEG Video Decoder"    {25AD5740-4DE0-4CF8-952A-2AEF53AC4321}    0x005fffff    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2mcdsmpeg.ax"
DSH    YV12    "MainConcept (Adobe2) H.264 Encoder"    {FF890B51-A4C5-4B19-87CF-65D86EC12F1C}    0x00200000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2esh264.ax"
DSH    YV12    "MainConcept (Adobe2) H.264 Encoder"    {FF890B51-A4C5-4B19-87CF-65D86EC12F1C}    0x00200000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2esh264.ax"
DSH    YV12    "MainConcept (Adobe2) H.264 Encoder"    {FF890B51-A4C5-4B19-87CF-65D86EC12F1C}    0x00200000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2esh264.ax"
DSH    YV12    "MainConcept (Adobe2) H.264 Encoder"    {FF890B51-A4C5-4B19-87CF-65D86EC12F1C}    0x00200000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2esh264.ax"
DSH    YV12    "MainConcept (Adobe2) H.264 Encoder"    {FF890B51-A4C5-4B19-87CF-65D86EC12F1C}    0x00200000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2esh264.ax"
DSH    YV12    "MainConcept (Adobe2) H.264 Encoder"    {FF890B51-A4C5-4B19-87CF-65D86EC12F1C}    0x00200000    ** File Missing: "C:\Program Files (x86)\Adobe\Adobe Premiere Pro CS4\ad2esh264.ax"